Difference between revisions of "903.3 Ground-Mounted Sign Supports"

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==903.3.1 Ground-Mounted Sign Installation==
==903.3.1 Post-Mounted Sign Installation==
 
 
 
'''Guidance.''' Signs should be post-mounted whenever possible unless mounting overhead is justified.
 
 
 
'''Standard.''' All post-mounted structural signs and sheet signs shall be mounted on pipe posts, wide flange (WF) fabricated steel posts, u-channel posts, perforated square steel tube posts or wood posts as shown in the standard plans.
 
 
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|[http://epg.modot.mo.gov/documents/903.2aPrintableSignpostSelectionGuide.xls Printable Signpost Selection Guide for use in the field]
 
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'''Guidance.''' Signs should be ground-mounted whenever possible unless mounting overhead is justified or required.
  
Cross-sections of relocated or new signs shall be drawn and included in the final plans. The cross-sections are drawn to a scale of 1 in. = 5 ft. (1:50) to allow for scaling of quantities. Random grid lines shall be used to draw the cross-section and elevations are not shown. All cross-sections shall be drawn as the driver views the sign face. A note shall be added to the cross-section if the footing depth is greater than the minimum shown in the standard plans.
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'''Standard.''' If signs are placed on existing supports, they shall meet other placement criteria contained in this article.
  
The following information shall be shown for each sign:
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Utility and light poles shall not be used to mount signs as they are either not the property and maintenance responsibility of MoDOT or are not designed to carry the additional wind loading a sign adds to the structure.
:* Sign number
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:* Station
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Option. In areas with space restrictions, available sign truss columns, signal poles, bridge columns, or other significant MoDOT structures, excluding roadway lighting structures, may be used to mount flat sheet aluminum signs.
:* Edge of traveled way
 
:* Edge of shoulder
 
:* Sign dimensions
 
:* Guardrail and curb locations
 
:* Post configuration
 
:* All non-standard horizontal and vertical clearances
 
:* Backing bars and post lengths
 
 
 
For multiple post designs, the posts shall be numbered from left to right, and only one post design type per sign shall be used.
 
 
 
Existing signs relocated to new posts and posts being used in place shall be shown with dashed lines.
 
 
 
All signs that are back-to-back shall be noted and the far sign shall be shown with dashed lines.
 
 
 
It is not necessary to outline the footing width and depth since this information is noted in the standard plans.
 
 
 
The post stub length shall be shown below the finished ground line in order to scale the correct post pay length.
 
 
 
'''Guidance.''' Utility and light poles should not be used to mount signs as they are either not the property and maintenance responsibly of MoDOT or are not designed to carry the additional wind loading a sign adds to the structure.
 
 
 
'''Option.'''  In areas with space restrictions, available sign truss columns, signal poles, bridge columns or other significant MoDOT structures, excluding roadway lighting structures, may be used to mount flat sheet aluminum signs.
 
 
 
'''Support.''' See [https://www.modot.org/media/16921 Standard Plan 903.03] for recommended footing depths for various post designs and slopes.
 
  
 
==903.3.2 Lateral Offset (MUTCD Section 2A.19)==
 
==903.3.2 Lateral Offset (MUTCD Section 2A.19)==
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'''Support.''' The minimum lateral offset is intended to keep trucks and cars that use the shoulders from striking the signs or supports, while keeping signs and object markers close enough to the roadway to be effective.
  
'''Standard.''' Post-mounted sign supports shall be crashworthy (breakaway, yielding or shielded with a longitudinal barrier or crash cushion) if within the clear zone.
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'''Standard.''' Ground-mounted sign supports shall be crashworthy and meet the latest federal crash standards at the time of installation.  
 
 
'''Guidance.'''  For post-mounted signs, the minimum lateral offset should be 12 ft. from the edge of the travelway.  If an existing shoulder is wider than 6 ft., the minimum lateral offset for post-mounted signs should be 6 ft. from the edge of the shoulder or front face of curb. 
 
 
 
Where existing signs are located within 6 ft. of a utility pole, they should be relocated to provide a minimum distance of 12 ft. where practical through normal sign replacement. 
 
 
 
EXIT signs placed in the gore only require a 2 ft. lateral offset from both edges of shoulder or front face of curbs.
 
 
 
For divisional and channelizing islands, a 2 ft. lateral offset should be maintained between the edge of sign and the front face of curb.  For islands with restricted width the sign should not extend beyond the curb.  When signing at the nose of a 4 ft. median, a 1 ft. lateral offset is acceptable between the edge of sign and the front face of curb.
 
  
Maximum clearances will depend on roadway geometrics, profiles, and cross-sections, which all affect the visibility of the sign. Sheet type and structural type signs are generally to be placed no more than 15 ft. from the edge of shoulder.
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'''Guidance.''' The provisions below should be applied unless specifically stated otherwise in the EPG for a particular sign or object marker. For ground-mounted signs, the minimum lateral offset should be 12 ft. from the edge of the travelway. If an existing shoulder is wider than 6 ft., the minimum lateral offset for ground-mounted signs should be 6 ft. from the edge of the shoulder or front face of curb.  See figures 903.2.26.1 and 903.2.26.2 which illustrate typical examples of the lateral offset requirements contained in this portion of the article.  
  
New sign installations should be a minimum distance of 12 ft. from existing utility poles.
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Maximum offset will depend on roadway geometrics, profiles, and cross-sections, which all affect the visibility of the sign. Signs are generally to be placed no more than 15 ft. from the edge of shoulder.  
[[image:903.2.1 trucks.jpg|left|175px]]
 
'''Support.'''  The minimum lateral offset is intended to keep trucks and cars that use the shoulders from striking the signs or supports.
 
  
It is acceptable to adjust the standard lateral offset to obtain a better cross-section and still maintain sign effectiveness and visibility.  For example, signposts are not placed in the center of ditches; therefore the lateral offset may be adjusted to better span a flat bottom ditch.  Existing drainage structures, pull boxes and sidewalks may also affect lateral offset.
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Ground-mounted signs placed in a gore only requires a minimum of 2 ft. lateral offset from edges of shoulder, face of barrier walls or guard rail.  
  
Lateral offset are not noted on [http://epg.modot.org/forms/DE%202017%20Forms/DELiaison/D-29.pdf Form D-29] unless they differ from the standard 6 ft. offset.
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For divisional and channelizing islands, a 2 ft. lateral offset should be maintained between the edge of sign and the front face of curb. For islands with restricted width the sign should not extend beyond the curb face.  
  
'''Guidance.'''  All supports should be located as far as practical from the edge of the shoulder.   Exposing traffic to sign supports should be minimized by placing signs in such locations as behind existing roadside barriers or on over-crossing structures.
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'''Option.'''  Deviation from the standard lateral offset may be used if a signs effectiveness and visibility are maintained to account for variations in roadside features. For example, to avoid placing signposts in the flow line of a ditch, avoiding drainage structures, pull boxes or sidewalks.
  
A minimum sight distance of signs should be maintainedThere should be a minimum of 60 ft. of sight distance for each inch of letter height with a 1000 ft. minimum for all mainline signs.  Signs on conventional roads should have a minimum 250 ft. sight distance.  Refer to [[903.6 Warning Signs#Table 903.6.5 Warning Sign Sizes|Tables 903.6.5]] and [[903.6 Warning Signs#Table 903.6.6 Horizontal Alignment Sign Usage|903.6.6]]When this is not possible, relocating or providing additional advance signing should be considered.
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'''Option.''' Lesser lateral offsets may be used in business, commercial or residential areas where limited space is available to place signs due to limited right of way, sidewalks or other restrictions which keep the sign from being installed at the correct offsetIn these cases, the edge of the sign may be placed up to, but not beyond the face of the curb making every effort to maximize the offset with the space available.  
  
'''Option.'''  Where permitted, signs may be placed on existing supports used for other purposes, such as highway traffic signal supports. 
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'''Guidance.''' Ground-mounted sign supports should not intrude into the usable width of a sidewalk or other pedestrian facility.  
 
 
'''Standard.'''  If signs are placed on existing supports, they shall meet other placement criteria contained in this article.
 
 
 
'''Option.'''  Lesser lateral offsets may be used on connecting roadways or ramps at interchanges, but not less than 6 ft. from the edge of the travelway.  In urban areas where it is impractical to locate a sign with the lateral offset prescribed by this article, a lateral offset of at least 2 ft. may be used.  A lateral offset of at least 1 ft. from the face of the curb may be used in business, commercial or residential areas where sidewalk width is limited or where existing poles are close to the curb.
 
 
 
'''Guidance.''' Post-mounted sign supports should not intrude into the usable width of a sidewalk or other pedestrian facility.
 
 
 
'''Support.'''  [[903.2 Extent of Signing#Fig. 903.2.26.1 Examples|Figs. 903.2.26.1 and 903.2.26.2]] illustrate some examples of the lateral offset requirements contained in this portion of the article.
 
 
 
It is acceptable to adjust the standard lateral offset to obtain a better cross-section and still maintain sign effectiveness and visibility.  For example, signposts are not placed in the center of ditches, therefore the lateral offset may be adjusted to better span a flat bottom ditch.  Existing drainage structures, pull boxes and sidewalks may also affect lateral offset.
 
  
 
==903.3.3 Mounting Height (MUTCD Section 2A.18)==
 
==903.3.3 Mounting Height (MUTCD Section 2A.18)==
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'''Support.'''  Installing signs at the proper mounting height is critical not only for the sign to be seen and function, but also to the functionality of the breakaway design for each type of sign post.  Mounting heights are typically listed as “nominal” as it is critical to keep the signs a minimum distance above the ground, however, signs installed excessively high also have issues, such as:
  
'''Standard.'''  The provisions below shall apply unless specifically stated otherwise for a particular sign or object marker elsewhere in the EPG.
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:* Place signs outside of the drivers line of sight
 
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:* Place signs outside the effective range of vehicle headlights at night making signs less visible
Mounting heights for single wide-flange and all post designs are set from the edge of travelway to the bottom of the lowest sign.  Mounting heights for multiple wide-flange posts are set from the edge of travelway to the bottom of the lowest sign, or the length of the shortest post, whichever requirement provides the higher clearance.  Mounting heights for different designs are shown in the standard plans.
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:* Signs mounted too tall are more susceptible to wind resulting in signs being pushed out of plumb or being blown over
  
Supports for sheet SH signs, such as regulatory, warning and route shield markers, are designed to provide a mounting height of 7 ft. 0 in.  
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===903.3.3.1 Mounting Height – U-Channel, Wood, Perforated Square Steel Tube (PSST) and Pipe Posts (MUTCD Section 2A.18)===
  
All two- and three-post signs (any LOGO sign or sign with white legend on green, blue or brown sheeting) have a minimum 7 ft. 6 in. clearance from the edge of travelwayAlso, the shortest post is a minimum of 7 ft. 9 in. above the ground line to the bottom of the lowest signThis will provide sufficient post length to allow hinge plate installation, provide a 7 ft. 0 in.  clearance for errant vehicle impacts, and a 6 in. field adjustment.
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'''Support.'''  There are typically two mounting heights for signs on u-channel, wood, PSST and pipe posts, 5 feet and 7 feetTraditionally, the 5-foot mounting height has been applied to “rural” areas and the 7-foot mounting high applied to “urban” areas or within incorporated city limits. However, the term “urban” has more to do with the conditions the signs are being installed within and less about being located within an incorporated city limitThe purpose of the 7-foot mounting height is to provide clearance for passing bicycle and pedestrian traffic, making the sign more visible over parked vehicles along the roadway and permits improved sight distance to drivers permitting them to see below the sign.  
  
Due to wide-flange post limitations, large mounting heights of 25 ft. or more are avoided by either moving the sign or considering a truss-mounted sign.
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The 7-foot mounting height also applies to all freeway and expressway applications to enhance long distance visibility.
  
All two- and three-wide flange post signs contain hinge plates as shown in the standard plans.  On the shortest post a mounting height of 7 ft. 9 in. is maintained from ground line to the bottom of the lowest sign.  This will allow sufficient length of post for a hinge point cut line 3 in. from the bottom of the lowest sign.  Maintaining this clearance on the shortest post is critical for exit gore and other signs located between roadways and have high exposure to traffic.
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'''Standard.''' Standard Plans 903 shall be referenced for specific installation and mounting height details. The details in Standard Plans 903 and this section of the EPG shall apply to all signs unless specifically stated otherwise for a specific sign or object marker elsewhere in the EPG.
  
The minimum height, measured vertically from the bottom of the sign to the elevation of the near edge of the pavement, of signs installed at the side of the road in rural areas shall be 5 feet.
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The minimum mounting height of a sign shall be measured vertically from the bottom of the sign to the elevation of the near edge of the pavement.  Minimum sign mounting heights shall be as follows:
  
The minimum height, measured vertically from the bottom of the sign to the top of the curb, or in the absence of curb, measured vertically from the bottom of the sign to the elevation of the near edge of the travelway, of signs installed at the side of the road where parking or pedestrian movements are likely to occur, or where the view of the sign might be obstructed, shall be 7 feet.
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:* Sign located in rural areas – 5 feet,  
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:* Sign located in urban areas – 7 feet,
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:* Signs located on freeways and expressways – 7 feet.  
  
'''Option.'''  The height to the bottom of a secondary sign mounted below another sign may be 1 ft. less than the height specified in this article.
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The length of post measured from the bottom of the sign to the ground shall also be a minimum of 5 feet. If the length of any post within a sign assembly measures less than 5 feet from the bottom of the sign to the ground, the minimum sign mounting height shall be increased to achieve the minimum 5-foot post length.  
  
Signs are placed 30 ft. or more from the edge of the travelway may be installed with a minimum height of 5 ft., measured vertically from the bottom of the sign to the elevation of the near edge of the pavement.
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'''Option.'''  Signs may be installed at 5 feet within the boundaries of incorporated city limits if the all following conditions apply:
  
A route sign assembly consisting of a route sign and auxiliary signs (see Route Sign Assemblies) may be treated as a single sign for the purposes of this article.
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:* The sign is located outside of business, commercial or residential areas where there are no high densities of entrances and cross street intersections
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:* There is no on street parking
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:* There are no sidewalks with bicycle or pedestrian traffic
  
All posts except structural posts should have a minimum clearance of 5 ft. above the driving surface with a minimum post length of 5 ft. above the ground.
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If a secondary sign is mounted below the primary sign on the same sign post(s), the mounting height for the assembly, measured from the near edge of the pavement to the bottom of the secondary sign, may be 1 foot lower than the minimums listed above.
  
The mounting height may be adjusted when supports are located near the edge of the right of way on a steep backslope to avoid the sometimes less desirable alternative of placing the sign closer to the roadway.  
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In cases where signs are located on steep back slopes, it may be advantageous to relocate the sign forward or back from the proposed location to an area that is flatter to avoid a sign being mounted too high.  
  
'''Support.'''  [[903.2 Extent of Signing#Fig. 903.2.26.1 Examples|Fig. 903.2.26.1]] illustrates some examples of the mounting height requirements contained in this article.
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'''Guidance.'''  Signs located outside of incorporated city limits that are located in areas having characteristics of an urban area, such as around businesses, heavy residential areas, areas with on street parking and areas with sidewalks which support bicycle and pedestrian traffic, should be installed at 7 feet.
  
==903.3.4 Pipe Posts==
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Route marking assemblies consisting of a route sign and auxiliary signs should be treated as a single sign for the purposes of sign mounting height.  
  
'''Support.''' Steel pipe posts are used for sheet (SH) signs up to 30 ft<sup>2</sup>.  Available pipe size inside diameters are 2-1/2 in., 3 in. and 4 inch.  Post sizes are determined using the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]. A [http://epg.modot.mo.gov/documents/903.2aPrintableSignpostSelectionGuide.xls printable Signpost Selection Guide for use in the field] is also available.  It is recommended to provide a two-post design for sheet sign widths greater than 3 ft. 6 in. (other than diamonds or the 48 in. and 60 in. YIELD signs).  The extreme width sign, W, is calculated as: W = (area of signs + area of exposed backing bars + area of post above bottom of sign)/(extreme height of sign).  For additional information, consult the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]. A [[media:903.3.4 Pipe Quick Reference.pdf|Pipe Quick Reference]] is also available for commonly used signs and assemblies encountered in the field.
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'''Support.''' Fig. 903.2.26.1 illustrates typical examples of the mounting height requirements contained for signs installed on U-Channel, Wood, PSST and Pipe Posts.
  
Pipe posts should be used for route marker assemblies due to their multi-directional breakaway characteristics.
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===903.3.3.2 Mounting Height – Wide Flange (I-Beam) Posts (MUTCD Section 2A.18)===
  
It is desirable to keep posts out of the ditch flow line, when possible.
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'''Support.'''  Installing signs at the proper mounting height is critical not only for the sign to be seen and function, but also to the functionality of the breakaway designProper mounting height is more critical for breakaway function on Wide Flange posts compared to all other posts due to the hinge component of this post design.  As with the other post types, mounting heights for Wide Flange posts are listed as “nominal” as excessive mounting heights have the same negative effects for these installations as exists with the other post types.  Wide Flange post mounting heights are greater than other posts, so in areas with back slopes it is recommended to seek out a flatter location in advance or downstream of the original installation to keep the sign as low as possible.
   
 
Breakaway assemblies on pipe posts are integral with the post design and are incidental to the cost of the post.
 
  
The standard plans show design data for computing the weights (masses) of pipe posts, along with data for computing footing quantities.
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Minimum mounting heights for Wide Flange post installations are not related to rural or urban classifications, but are directly related to how the breakaway system functions.  Standard Plans 903 provides details on the nominal mounting heights on wide flange posts. Key details to focus on are:
  
==903.3.5 Wide Flange (WF) Posts==
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:* No wide flange post can be shorter than 7’ 9” measured from the hinge to the top of the stub.
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:* The hinge point is always below the lowest sign which is attached to the wide flange post.
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:* Nominal mounting heights vary depending if there is one sign mounted on the posts or two.
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:* For signs located in areas of back slopes, the minimum mounting height may have to be increased, or the sign installed in a different location, in order to achieve the minimum post length of 7ft. 9 in.
  
'''Support.''' WF posts are used for mounting signs larger than 30 ft<sup>2</sup>.  The post design number is determined from [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]] when a sign is mounted alone or with an exit panel above the main sign.  A [http://epg.modot.mo.gov/documents/903.2aPrintableSignpostSelectionGuide.xls printable Signpost Selection Guide for use in the field] is also available.  The extreme width sign, W, is calculated as: W = (area of signs + area of exposed backing bars + area of post above bottom of sign)/(extreme height of sign).
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==903.3.4 Ground-Mounted Sign Support Selection==
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'''Support.''' The majority of MoDOT signs are installed and supported on one of 5 types of ground-mounted sign supports or sign posts.  The selection of sign post is based on many factors, but primarily on the size of sign being installed and the type of roadway the sign is being installed alongThere is some overlap in sign post applications; more than one sign post may be applicable to a given installation.  The final selection of the post type is based on the attributes needed for a support as discussed in each classification of sign post below.
  
For post designs No. 3, No. 4, No.5 and No.6 having weights greater than 18 lbs/ft., posts shall be spaced at least 7 ft. apartFor post designs No. 1 and No. 2, posts may be spaced less than 7 ft. apartDo not use three No. 1 or No. 2 posts with a sign width of less than 10 feet 6 inches.
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The number of posts needed to support a sign is primarily based on the width of a sign. Typically, signs 48 inches in width and wider are installed on two or more posts.  This requirement is based on two factors, the capacity of the post and the long-term stability of the assemblyA wide sign installed on one post will place a torsional force onto a post and in windy conditions can result in an assembly not staying plumb and, in some cases, an actual failure of the post itself.
  
In many cases, two designs are possible using a two- or three-post design chartThere are no special criteria for determining which of these two designs to useGenerally, signs from 6 to 17 ft. wide will be designed for two posts, while signs wider than 17 ft. requires three postsIt is desirable to keep posts out of the ditch flow line and median, when possible.  This may be a deciding factor for a two-post or three-post design.
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'''Standard.''' The selection of the proper size of sign post shall be based on the sign selection tools listed belowThese tools will specify if a post type has the capability to support the sign in question and then specify what size post is required based on the requirements of the installation. Before the correct size of PSST or Wide Flange post can be selected, the length of the longest post must first be determinedIn order to determine this, the offset and mounting height must first be determined.  
  
A single WF post shall not be used to support route marker assemblies. For larger two-post sign design combinations consult the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]The next higher post design is used when in doubt.
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===903.3.4.1 U-Channel Posts===
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'''Support.''' MoDOT utilizes two primary sizes of U-Channel Posts, a 3lb/ft high carbon, rerolled rail steel post for sign installations and a low carbon steel 1lb/ft post for road side delineation.   
  
[https://www.modot.org/media/16921 Standard Plan 903.03] shows data needed for computing the weights (masses) of WF posts, along with data to compute footing quantities.
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U-channel posts can be used to support MoDOT’s small signs, such as no parking signs, object markers and chevrons on two lane roadways. U-channel posts are typically not suited to support larger permanent signs as they have limited torsional rigidity and have less ability to hold a larger sign steady in windy conditions. These are typically the most economical posts to use to support smaller signs and given these types of signs tend to be installed closer to the roadway their ability to yield more easily to impacts means they pose less of a damage risk to vehicles.  U-channel posts are typically installed by driving the post into the ground without a stub or anchor, however, there is a stub / post installation option available which is detailed in the standard plans.
  
Breakaway assemblies on WF posts are integral with the post design and are incidental to the cost of the post.
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U-Channel posts are considered breakaway with no additional breakaway devices needing to be added.  While there are breakaway devices available for U-channel posts, MoDOT’s use of this type of post for smaller signs typically doesn’t justify their use.  A U-channel post’s breakaway is typically a yielding function, meaning as a vehicle impacts the assembly, the post yields and lies down in front of the vehicle so it can pass over the assembly.  
  
==903.3.6 U-Channel Posts==
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'''Standard.''' U-channel posts shall be installed in accordance with the details found in Standard Plans 903. Sign post selection tools shall be used to determine sign sizes U-channel posts can support and the number of posts needed. 
  
'''Support.''' Steel channel posts are authorized as an alternate to wood posts in accordance with the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]].
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===903.3.4.2 Wood Posts===
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'''Support.''' MoDOT’s specs permit three sizes of wood posts to be used, 4 in. x 4 in., 4 in. x 6 in., or 6 in. x 6 in.  MoDOT’s wood posts are pressure treated to promote longer life and resist rot and insect damage.  Wood posts were once MoDOT’s primary post to support signs on two lane roadways; however, due to issues with material stability PSST posts have become MoDOT’s standard post.
  
These supports are galvanized 3 lb. steel posts used primarily for installing sheet (SH) signs.  Details of these posts are shown on Standard Plan 903.03. 
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When used, wood posts are capable of supporting most sign assemblies on two lane roadways, from route marker assemblies, speed limit signs, warning signs and distance and destination signs.  The use of a high quality wood post and proper installation is the key to a successful installation.
  
These posts are paid for by linear foot. No additional payment is made for hardware. The number of posts to be used is based on the sign area for each installation and is determined using the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]. Breakaway assemblies are not required for steel channel posts.
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'''Guidance.''' The continued use should take into consideration the special characteristics listed in this section.
  
'''Guidance.''' Use of these posts should be based on discussions with district Traffic.
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Proper installation is also critical for the stability of the sign assembly. The wood post should be placed a minimum of 36 inches into the ground, deeper for larger signs or in areas where the soil is weak or sandy, to keep the sign post plumbWhen backfilling the hole, material should be added in lifts, or levels, in order to properly compact the backfill.  Loose or fine materials, such as sand, sandy soil or dry concrete mix typically will not provide a long term solid backfill and can result in the post falling out of plumb over time.  
  
'''Option.''' The steel channel posts may have an optional soil or stabilizer plate (¼ in. x 10 in. x 10 in.) secured to the lower portion of the post by a minimum of two 5/16 in. diameter sign bolts so that the final location of the plate on the driven post is approximately 6 in. below the ground surface. This plate may be required on posts driven into soils typically encountered in northern or southeast Missouri or river bottoms. A typical 14 ft. post is driven a minimum of 2.5 ft. into the ground with 7.25 ft. maximum from the ground to the bottom of the sign, with 3.5 ft. behind the sign.
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MoDOT’s specifications should be followed when purchasing wood sign posts. These specifications address a posts load capacity, breakaway attributes and the compatibility between the pressure treatment chemicals and our aluminum signs and sign hardware.    
  
Steel channel posts may be direct driven or installed by means of a stub.
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'''Option.'''  While the soil originally removed from the hole can be used to back fill around the post other alternatives may be used, such as smaller quarry rock with the crushing fines mixed in, concreted mix or expanding urethane foam.  
  
'''Standard.''' Stubs, if used, shall be installed in accordance with [https://www.modot.org/media/16921 Standard Plan 903.03]
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'''Support.''' Wood posts are considered breakaway without an add-on breakaway device; however, some sizes of post do need special preparation.  4 in. x 4 in. wood post are considered breakaway without any special modifications; however, 4 in. x 6 in. and 6 in. x 6 in. posts must be cross drilled at the base to weaken them so they will break away.   The size of the holes and where they are drilled is critical to these posts meeting breakaway requirements. The details for these holes are found in the Standard Plans 903, it is important to note these breakaway holes are drilled in the sides of the post, not in the front of the post where the sign is mounted.
  
==903.3.7 Wood Posts==
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'''Standard.'''  If wood posts are used, the proper size and number of posts shall be determined by using the post selection tools.
[[image:903.2.6.jpg|right|250px]]
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[[image:903.3.7.jpg|thumb|center|700px|<center>'''Fig. 903.3.4.2, Details for Wood Posts Requiring Breakaway Design'''</center>]]
'''Support.''' These supports are pressure treated 4 in. x 4 in., 4 in. x 6 in., or 6 in. x 6 in. wood posts used primarily for installing sheet (SH) signs.  Details of these posts are shown on [https://www.modot.org/media/16921 Standard Plan 903.03]These posts are paid for by the linear foot. No additional payment is made for slotting the larger posts or for hardwareThe number of posts to be used is based on the sign area for each installation and is determined using the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]. A [http://epg.modot.mo.gov/documents/903.2aPrintableSignpostSelectionGuide.xls printable Signpost Selection Guide for use in the field] is also available.
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'''History.''' One of the earliest issues experienced with wood posts is their tendency to warp and twist, both before and after installation. Keeping a sign plumb and appropriately oriented to the roadway is critical to maintain the sign’s legibility and night time retroreflectivity performance. This aspect of wood posts resulted in significant waste of inventory when the posts warped and twisted before being used and increased work load on signing crews who had to correct warped and twisted posts after installationsAnother concern with the use of wood posts was the installation required a hole to be dug, the posts set and property back filled so the sign would remain upright.  If soil conditions prohibited a hole being dug deep enough or the back fill not capable for being compacted sufficiently the assembly would fall out of plumbAlong with these installation aspects, a wood post sign assembly can be very heavy, especially when the pressure treated wood is still wet with the pressure treating fluids and this can result in the need for additional people to set the post and/or increased risk of injury setting the post by hand.
  
'''Standard.''' Signs shall be mounted on the 4 in. face side of the 4 in. x 6 in. wood post.
+
Towards the end of MoDOT’s reliance on wood posts a new issue was identified relating to the more environmentally friendly treatment process called ACQ (Ammoniacal Copper Quaternary). ACQ replaced CCA (Chromated Copper Arsenate) for residential applications as CCA had chemical component which were not recommended for routine contact with skin.  However, unlike CCA, ACQ (especially early versions) turned out to be very corrosive to metals, especially to aluminum.  This corrosive nature requires special fasteners to resist this corrosive effect. Early applications of ACQ in other states realized serious sign corrosion to the point the sign would fall off the post in a matter of a few years. While it appears this has improved, special fasteners with special protective coatings are still recommended for use with ACQ posts. As a result, ACQ posts do not meet MoDOT’s specifications and should not be used to support signs. CCA treated posts are still MoDOT’s standard for wood posts, however, it is not commonly available at local home improvement centers and at many lumber yards. Due to MoDOT’s limited use of this product contract purchasing typically is not economical or possible.
Required drilling of these posts to create a breakaway system shall be performed according to Fig. 903.3.7.
 
  
'''Guidance.''' Use of these posts should be based on discussions with district Traffic.
+
===903.3.4.3 Perforated Square Steel Tube Posts (PSST)===
 +
'''Support.'''   MoDOT utilizes two sizes of PSST, 2 in. and 2.5 in., both being made from 12-gauge steel.  PSST became MoDOT’s standard post for most sign installation applications on two lane roadways in the early 2000’s, replacing wood posts.  PSST usage has since expanded to some applications on freeways and expressways.
  
In general, one-fourth of the length of a wood signpost should be in the ground. The minimum length of post in the ground should be 30 in. to ensure a stable installation.   
+
Unlike U-channel or Wood posts, PSST utilizes a ground anchor, or footing, in which the post is then inserted.  MoDOT has several options in its specifications with respect to ground anchor/foundation systems, the uses of each option is heavily based on the soil conditions in the area of the installation and the direction district operations has chosen based on what they have found to work the best for each of their areasAll MoDOT PSST anchors/footings are a minimum of 36” deep, the anchor/footing types for PSST are:
  
[[image:903.3.7.jpg|thumb|center|700px|<center>'''Fig. 903.3.7. Details for Wood Posts Requiring Breakaway Design'''</center>]]
+
:* 12 Gauge PSST Anchor – this is the basic anchor for 2 in. PSST posts, a 12-gauge anchor does not exist for 2.5 in. PSST posts. 
 +
:* 12 Gauge Omni PSST Anchor – this is a 12-gauge PSST anchor with 4 soil stabilization plates added to the anchor to increase soil surface area to help keep signs plumb in weaker soils and/or in windy areas.
 +
:* 7 Gauge Anchor – this is a heavy wall box tube anchor which is the basic anchor for 2.5 in. PSST posts and an optional heavy anchor for 2 in. PSST posts.  This anchor is typically used for 2 in. PSST posts in rocky ground where a 12-gauge anchor may deform when driven.  7 gauge anchors only have holes at the top of the tube. The connection between a 7 gauge anchor and a PSST post is accomplished using two shoulder bolts installed at 90 degree angles to each other.
 +
:* 7 Gauge Omni Anchor – this is a 7-gauge anchor with 4 soil stabilization plates added to the anchor to increase soil surface area to help keep signs plumb in weaker soils and/or in windy areas, available for both 2 in. and 2.5 in. PSST posts. 
 +
:* Concrete Footings – In some applications it may be desired to install a concrete footing for PSST, similar to the footings for a Pipe Post or Wide Flange Post. Concrete footings can provide a stronger footing compared to one of the directly driven anchors listed above. A concrete footing may also be required in cases where the ground is too hard or rocky to direct drive an anchor and a hole for the anchor may need to be dug in order to install the anchor. All concrete footing installations use a 7-gauge anchor to provide both a durable foundation and to eliminate concrete from flowing through the holes of a normal 12-gauge PSST anchor.
 +
:* Expanding Urethane Footings – This is an alternate to a concrete footing.  This permits the footing and the sign to be installed in one trip compared to concrete, which requires a second trip to allow the concrete to cure. The installation requirements for an expanding foam footing are the same as a concrete footing except for the diameter of the footing, which is smaller.  It is important to make sure the expanding foam used meets MoDOT specifications as not all foam products are acceptable to support a breakaway sign.
  
===Splicing Wood Posts===
+
The connection between the PSST and Anchors also vary based on the anchor gauge:
  
'''Standard.''' The district shall retain salvageable broken wood signposts for recycling.  
+
:* 12-gauge anchor / 12-gauge post - The connection between a 12-gauge anchor and the PSST post is accomplished using a corner bolt.  The corner bolt pulls the post into a corner of the anchor and eliminates any slack or play between the post and the anchor.
 +
:* 7-gauge anchor / 12-gauge post - Unlike a 12-gauge anchor and 12-gauge post which telescope together with limited slack or play, the fit between a 7-gauge anchor and 12-gauge PSST post is much looser and the radii of each do not match so a corner bolt will not eliminate the slack or play between these two devices. The corner bolts installed at 90-degree angles corrects this issue; the shoulder of the bolt will pass through the holes in the 7-gauge anchor, but not through the holes in the post.  As a result the two bolts push and lock the post in two directions making a solid connection.
 +
:* Add-on breakaway devices – when required/used, the manufacture’s recommendations and hardware (if supplied) need to be used to connect the anchor, breakaway and post together.
  
'''Support.''' Three methods have been established for the purpose of splicing these posts. Figs. 903.3.7.1 and 903.3.7.2 represent the two methods for splicing posts both in the field and in the shop. Fig. 903.3.7.1 represents the most feasible and economical method used for splicing posts in the field. Fig. 903.3.7.2 depicts splices that can be performed in the shop or field as dictated by conditions and equipment.  
+
Breakaway aspects of PSST are a little more complicated compared to other MoDOT posts, the requirement for an add-on breakaway device heavily depends on the size and number of posts needed to support the sign. It is important to follow the guidance found in the sign post selection tools and MoDOT’s standard plans to determine when an add-on breakaway device is required and when it is not. In applications where add-on breakaway devices are not required/used, PSST breaks away like a U-channel post in a yielding fashion, typically staying attached to the ground and lying down in front of the vehicle so the vehicle can pass over the assembly. However, when an add-on breakaway device is used the breakaway function changes and the assembly is designed to break away from the ground and permit the vehicle to pass under the airborne assembly.
  
'''Guidance.''' For the method as shown in Fig. 903.3.7.1, the splice should be located as near the top of the post as possible (minimum of 30 in. above the ground line) and the sign mounted on the post perpendicular to the "Z" shaped cut; that is, with the sign face perpendicular to the splicing bolts.
+
'''Standard.''' If PSST posts are used, they shall be either 2 in. or 2.5 in. 12-gauge posts.   The size and number of posts, as well as the requirement for add on breakaway devices, shall be determined using the post selection tools.  PSST posts shall be installed in accordance with Standard Plans 903.
  
[[image:903.3.7.1.jpg|thumb|center|700px|<center>'''Fig. 903.3.7.1. Wood Post Shop Splicing Details'''</center>]]
+
===903.3.4.4 Pipe Posts===
 +
'''Support.''' MoDOT utilizes three sizes of pipe post, 2 ½ in., 3 in. and 4 in.  An important fact to understand is pipe post sizes are based on the inside diameter (I.D.) of the pipe post and not the outside diameter, this is the industry standard for pipe measurement. This is critical in selecting the correct pipe from inventory as well as charging out the correct post to keep your inventory levels correct.
  
[[image:903.3.7.2.jpg|thumb|center|700px|<center>'''Fig. 903.3.7.2 Wood Post Shop/Field Splicing Details'''</center>]]
+
Pipe posts have a similar sign capacity as PSST, even though they would appear to be able to carry a larger sign load due to size and thickness of the steel pipe. While the post themselves are far stronger than PSST, it is the breakaway of the pipe post which primarily controls the sign load capacity of the post. The heavy-duty construction of a pipe post is not specifically related to sign load capacity but is more directly related to the durability of the post. Unlike PSST, which must be replaced after each vehicular impact, pipe posts are constructed with much thicker steel so the sign post can be impacted by a vehicle without being damaged and reinstalled for continued use. There are many pipe posts on our right of way that have been there for two or three generations of signs and are still functional so while they are heavier and more expensive, they are a long term investment and are far more durable.
  
==903.3.8 Perforated Square Steel Tube Posts==
+
Pipe posts are used for single and double sign post assemblies to support signs up to 30 sqft. These posts are typically used on freeways and expressways where signs are larger, wind speeds can be higher due to more open right of way and the sign may see larger snow load impact from plows pushing more snow from across multiple lanes to the right side of the roadway.  Their resistance to these larger loads is due to their heavier construction, but more importantly to their larger, deeper foundations.
  
'''Support.''' Perforated Square Steel Tube (PSST) is authorized as an alternate to wood posts in accordance with the Signpost Selection Guide. These supports are galvanized 2 in. or 2.5 insquare 12-gauge steel posts used primarily for installing sheet (SH) signsDetails of these posts are shown on Standard Plan 903.03.
+
Pipe posts are also the preferred post to support large route assemblies, especially on freeways and expresswaysIn the past, Wide Flange posts were once used to support these assemblies (and many remain in place) as the design of the post was well suited to attaching a series of backing bars needed to support the assembliesHowever, the multi-direction breakaway and high resistance to torsional or twisting forces makes Pipe posts the preferred post over the Wide Flange design.  
  
These posts are paid for by the linear foot, for each post used. An additional bid item must be included for the anchor sleeve for each post used and are also paid for by the linear foot. Omni-Directional anchors may be used for installation in weak or loose soil conditions. No additional payment will be made for hardware.  
+
Pipe posts are designed and fabricated with the breakaway device as part of the post / stub combination; as long as the post and stub breakaway is assembled correctly the post is capable of being impacted from any direction. Details for the assembly of this post system is found in Standard Plans 903, special attention must be paid to the placement of three breakaway bolts, the required and proper placement of all washers within the breakaway and most critically to the proper tightening and torque of the breakaway bolts.
  
Standard Plan 903.03 shows details for selection of anchor sleeve based on post size. The 7 ga. post anchor is used with 2 in. PSST post when the post will be installed in a concrete footing or as an option if rocky soil conditions exist.
+
'''Standard.'''  If Pipe posts are used, they shall be either 2 ½ in., 3 in. or 4 in. in size. The size and number of posts shall be determined using the post selection tools.  Pipe posts shall be installed in accordance with Standard Plans 903.
  
 +
===903.3.4.5 Wide Flange (I-Beam) Posts ===
 +
'''Support.''' MoDOT uses 6 sizes of Wide Flange posts, commonly referred to as Design #1, #2, #3, #4, #5 and #6, increasing in size and capacity respectively.  Wide Flange posts are typically used to support signs 30 ft2 and larger and are MoDOT’s highest capacity ground-mount sign support.  As with Pipe Posts, Wide Flange post are designed to be a more durable post intended to last multiple generations of signs and designed to be able to be impacted by vehicle and then reassembled and reused.
  
The number of posts to be used is based on the sign area for each installation and is determined using the [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]]. A [http://epg.modot.mo.gov/documents/903.2aPrintableSignpostSelectionGuide.xls printable Signpost Selection Guide for use in the field] and a [[media:903.3.8 PSST Quick Reference.pdf|PSST Quick Reference Guide]] for commonly used signs and assemblies encountered in the field is also available. Signs wider than 8 ft. should be mounted using Pipe or WF post.
+
Wide Flange post are designed and used to support large structural signs, signs made using extruded aluminum panels instead of flat sheet aluminum.  The cross section of a wide flange post being that of an I-beam permits structure signs to be easily attached to the post using post clips or “dog clamps” instead of using traditional sign bolts. These posts are traditionally used on freeways and expressways only; however, there may be special applications where they may be used on two lane roadways if the size of the sign is too large for other post options.
  
PSST posts work well in paved areas where replacement of conventional signs posts is difficult and time-consuming and where frequent knockdowns occur. An island at an urban intersection would be an example of this, where the concrete surfacing prevents easy sign replacement and where accident damage is frequent.
+
Wide Flange posts were once the standard to support large route assemblies on freeways and expressways, however, over time two weaknesses were identified that changed this direction, making Pipe posts the better option. The two weaknesses of Wide Flange posts used to support route assemblies are:
 
Breakaway devices are not required for PSST posts unless required by Signpost Selection Guide.
 
  
'''Option.''' PSST posts may be direct-driven or installed by means of a sleeve that is first installed and then the post inserted and attached to the sleeve by means of a corner bolt.  
+
:* Safety - Route assemblies many times are installed in and around intersections and in these locations it is theoretically possible some assemblies could be impacted from any direction of travel. Single Wide Flange posts are only breakaway in two directions and are not designed to be breakaway if impacted on either side, just the front and back of the sign.  Pipe posts are designed as a multi-breakaway post and can be impacted from any direction making them the better option for these installations. 
 +
:* Torsional / Twisting Force Resistance – Although Wide Flange posts are very strong, they do have a limited resistance to twisting moments when installed as a single post installation.  In wind prone locations, sign assemblies on a single Wide Flange post can begin to twist in the wind, and if this continues long enough, it can cause the post to fatigue and break off at the base.  Pipe posts have an extreme resistance to twisting and can resist much larger torsional forces compared to wide flange posts.
  
'''Guidance.''' Use of these posts should be based on discussions with district Traffic.
+
As with Pipe Posts, Wide Flange posts are fabricated with the breakaway system as part of the post / stub assembly.  While Wide Flange posts have a breakaway assembly at ground level like Pipe posts, they also require a hinge system located directly below the signThe hinge system permits the wide flange post (the portion from the ground to the bottom of the sign) to swing up out of the way of a vehicle when impacted without the upper portion of the post and the sign needing to move.  This reduces the mass that a vehicle must move when it impacts the post and in return reduces the impact energy to the car.
  
==903.3.9 Secondary Sign Supports==
+
Unlike all other MoDOT posts, there are minimum post spacing which must be taken into consideration when selecting the correct number and size of post. Wide Flange Posts are much heavier than any other MoDOT post and hitting two of these posts at the same time in most cases would impart too much energy to the vehicle and would not meet minimum breakaway standards. These special considerations are included in Standard Plans 903 which contains all of the fabrication and installation details for Wide Flange Posts, however, due to their critical nature they are also listed here:
  
'''Support.''' These supports are aluminum wide-flange posts used to attach service signs and exit number panels to structural signs. Details of these posts are shown in the standard plans.  There is no direct bid for these posts.
+
:* Wide Flange Post Designs #1 and #2 have no minimum post spacing requirements.
 +
:* Wide Flange Post Designs #1 or #2 shall not be installed in three post configurations supporting signs less than 11 feet width.  
  
==903.3.10 Backing Bars==
+
:* Wide Flange Post Designs #3, #4, #5 and #6 shall be spaced at least 7 ft. apart.
  
'''Support.''' Backing bars support wide SH signs and side-by-side route assemblies.  The standard plans show requirements for backing.  Lengths and the weight per foot of backing bars are shown in the standard plansBacking bars are totaled and included in the bid item for structural steel posts.  Backing bars are totaled on [http://epg.modot.org/forms/DE%202017%20Forms/DELiaison/D-29.pdf Form D-29]. If there is no structural steel posts, then the backing bars are included in the [http://www.modot.mo.gov/business/contractor_resources/biditemslisting.htm bid item] for pipe posts.
+
The post selection tool is designed to utilize two post installations over three post installations to help address minimum post spacing; it also reduces the number of footings which need to be constructedHowever, there are some general rules based on sign size used to judge the number post for different size ranges of signs:
  
==903.3.11 Hinge Plates==
+
:* Signs between 6 ft. and 17 ft. wide will typically be supported on two posts
 +
:* Signs wider than 17 ft. will typically be supported by three posts
 +
:* Signs of any size are not recommended to be installed on one Wide Flange post
  
[[image:903.2.10 Hinge Plate.jpg|right|275px]]
+
'''Standard.'''  If Wide Flange posts are used, they shall be either a structural #1, #2, #3, #4, #5 or #6 in design. The size and number of posts shall be determined using the post selection tools.  Wide Flange posts shall be installed in accordance with Standard Plans 903.
  
'''Support.''' Hinge plates are installed on all WF post designs as shown in the standard plans.  Hinge plate cut lines are 3 in. below the bottom of the lowest sign. The cut line is a minimum of 7 ft. 6 in. above the ground line on the shortest postNo direct pay is made for hinge plates.
+
==903.3.5 Secondary Sign Supports – Post Extensions==
 +
'''Support.''' These supports are 3 in. aluminum I-Beam used to attach exit number panels to the top of, or to hang a secondary sign below, structural signs on new installations. Details of these posts are shown in the Standard Plans 903.   
  
==903.3.12 Breakaway Assemblies==
+
'''Option.'''  There are occasions where modifications and/or additions must be made to existing sign installations where the existing posts are not long enough to support the new sign assembly.  In these cases, it is permissible to utilize secondary sign supports to effectively extend the primary sign posts to support signs a maximum of 3 feet taller than the existing primary sign posts.
  
'''Standard.''' All signposts shall be an approved breakaway assemblies design. All sign supports used shall be in compliance with this article or the Standard Plans. Breakaway assemblies shall not be required for U-channel or wood posts.
+
Secondary sign supports may only be used to allow taller signs to be installed on existing sign posts if the sign posts have the capacity to carry the larger sign based on sign post selection tools.
  
Sign trusses and other large sign support structures that are not breakaway shall be shielded.
+
If a new sign assembly is more than 3 ft taller than the existing primary sign posts, new sign posts shall be installed.
  
'''Support.''' Breakaway assemblies for PSST posts are totaled on [http://epg.modot.org/forms/DE%202017%20Forms/DELiaison/D-29.pdf Form D-29]. All assemblies are paid for with the same bid item. Breakaway assemblies on Pipe and WF posts are integral with the post design and are incidental to the cost of the post.
+
==903.3.6 Backing Bars==
 +
'''Support.''' Backing bars are typically used to support and stiffen wide flat sheet signs mounted on single sign post or to help support the individual signs which make up sign assemblies to form one unified sign assembly.  Details for backing bars can be found in Standard Plans 903.  
  
'''Guidance.''' The Signpost Selection Guide should be used to determine a breakaway assembly, the correct size and number of posts for installing signs.
+
==903.3.7 Breakaway Assemblies==
 +
'''Standard.''' All signposts installed on right of way shall meet federal breakaway standards and MoDOT standards.  Sign posts not meeting current standards, but met the standards at the time of their installation, may remain in place until the end of their service life.
  
'''Option.'''  For perforated square steel tube posts, a breakaway design may or may not be required depending on the configuration of the posts.  The [[Media:903.2a Signpost Selection Guide 2014.xls|Signpost Selection Guide]] should be referenced to make an appropriate determination.
+
Sign trusses and other large sign support structures that are not breakaway shall be protected by acceptable shielding, such as guard rail or barrier wall.  
Damaged breakaway signposts may be made into signpost stubs. This can be accomplished by cutting the post to the proper stub length, inverting it and using it as a stub in lieu of purchasing new stubs.
 
  
==903.3.13 Orientation (MUTCD Section 2A.20)==
+
'''Support.'''  4 in. x 4 in. wood posts do not need any modification to be breakaway, however 4 in. x 6 in. and 6 in. x 6 in. wood posts will need to be cross drilled to meet breakaway standards.  U-Channel posts do not require breakaway modifications if they are direct driven into the ground, however, if the ground stub and slice installation method is used the installation will need to be installed according to the Standard Plans 903 to meet breakaway requirements.  PSST will require breakaway devices added in certain applications based on sign and number of posts used for an installation. The sign post selection tools will indicate when a breakaway is required for PSST posts. Pipe and Wide Flange posts have the breakaway devices integrated into the post design.  
  
'''Support.''' The brightness of the sign may drop 24 percent when the normal lateral offset from edge of travelway is increased to 30 feet.  The legibility remains at an 80 percent level or higher when using the standard 6 ft. lateral offset.  The skew angle shown on the standard plans is valid for signs on tangent sections of road regardless of lateral offset distance.  The skew angle may be adjusted to maintain brightness and avoid glare for signs on curved sections of roadThe plans indicate which signs require a skew angle other than that shown in the standard plans.
+
==903.3.8 Sign Orientation (MUTCD Section 2A.20)==
 +
'''Support.''' The orientation of the face of a sign in relation to the driver and roadway is critical to visibility and legibility, especially at night.  The effectiveness of the retroreflective sheeting on a sign can be negatively impacted if the orientation of the sign face is not correct, due to incorrect installation and/or a sign post being damaged and knocked out of alignment.   
  
'''Guidance.''' Unless otherwise provided in the EPG, signs should be vertically mounted at right angles to the direction of, and facing, the traffic that they are intended to serve.
+
The orientation of a sign can also help reduce unwanted reflection or glare off of the sign faceThe skew angle, shown in Standard Plans 903, is designed to help address this glare issue for tangent sections.  
  
Where mirror reflection from the sign face is encountered to such a degree as to reduce legibility, the sign should be turned slightly away from the road.  Signs that are placed 30 ft. or more from the pavement edge should be turned toward the road.  On curved alignments, the angle of placement should be determined by the direction of approaching traffic rather than by the roadway edge at the point where the sign is located.
+
'''Guidance.''' Unless otherwise provided in the EPG, signs should be vertically mounted at approximately right angles to the direction of, and facing, the traffic that they are intended to serve, with an approximate 3 degree skew angle away from traffic.  
  
'''Option.'''  The standard skew angle is 93 degrees.  However, skew angle may be adjusted to maintain brightness and avoid glare for signs on curved sections of road.  On grades, sign faces may be tilted forward or back from vertical position to improve the viewing angle.
+
Signs that are placed 30 ft. or more from the pavement edge should have a skew angle that is turned toward the road to improve the effectiveness of the retroreflective sheeting.  
  
==903.3.14 Sign Identification Labels==
+
'''Option.''' While the standard skew angle is 93 degrees, the skew angle may be adjusted to maintain brightness and avoid glare for signs on curved sections of road. On roadways with significant grades, sign faces may be tilted forward or back from vertical position to improve the viewing angle.
  
'''Standard.'''  Every MoDOT sign, regardless of the type or style, shall have two Identification Labels on the sign. The first label is placed on the front of the sign and identifies the sign as belonging to MoDOT and defines the penalty for tampering with the sign.  The second label is placed on the back of the sign and identifies who fabricated the sign, their contact information and the date the sign was manufactured for warranty purposes. 
+
==903.3.9 Sign Mountings (MUTCD Section 2A.21)==
 
+
'''Support.'''  Attaching a sign properly to a sign support is critical in order to properly orient the sign in relation to the driver as well as provide a durable, long life installation.
'''Support.'''  Identification Label design and placement details are shown on Standard Plan 903.02.
+
 
+
'''Standard.'''  Plastic/nylon washers shall be used between the heads of all twist fasteners (such as screws, bolts or nuts) and the sign face to protect the sheeting from the twisting action of the fasteners.  
==903.3.15 Post and Mountings (MUTCD Section 2A.21)==
+
Signs shall be attached to each type of sign support in accordance with Standard Plans 903.
 
 
'''Standard.'''  Signposts, foundations, and mountings shall be so constructed as to hold signs in a proper and permanent position, and to resist swaying in the wind or displacement by vandalism.
 
 
 
Plastic/nylon washers shall be used between the heads of all twist fasteners (such as screws, bolts or nuts) and the sign sheeting to protect the sheeting from the twisting action of the bolt heads.  Plastic/nylon washers are available through the Sign Production Center for  districts.
 
 
 
'''Support.'''  The latest edition of AASHTO’s Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals contains additional information regarding posts and mounting.
 
 
 
'''Option.'''  Where engineering judgment indicates a need to draw attention to the sign during nighttime conditions, a strip of retroreflective material may be used on regulatory and warning sign supports.
 
 
 
'''Standard.'''  If a strip of retroreflective material is used on the sign support, it shall be at least 2 in. wide, it shall be placed for the full length of the support from the sign to within 2 ft. above the edge of the roadway, and its color shall match the background color of the sign, except that the color of the strip for the YIELD and DO NOT ENTER signs shall be red.
 
 
 
==903.3.16 Ordering Signs==
 
 
 
'''Standard.'''  All signs installed and maintained on state routes by MoDOT staff are acquired utilizing the department’s 3<sup>rd</sup> party sign fabrication contract.  When a sign need is determined, sign requests shall be submitted utilizing the vendor ordering component of SMS.  The vendor order component of SMS interfaces with Sam II to create a State Purchase Order, which shall then be submitted to TS for processing.  TS reviews all purchase orders to identify errors and to identify sign orders which require sign details to be created before being sent to the vendor.  Normal sign orders are submitted to the vendor each Wednesday and the vendor has 21 calendar days to deliver these signs to the districts.
 
 
 
'''Options.'''  If faster deliveries are required, there are provisions for 14- and 7-day delivery options. These special orders can be submitted any day of the week.  The vendor contract also has a provision for a 36-hour emergency order which may also be submitted any day of the week. However, this special delivery option does have limitations.
 
 
 
'''Standard.'''  The 36-hour delivery option shall only be utilized for emergency needs, including, but not limited to emergency road and bridge closures or emergency bridge weight limit changes.  Due to delivery issues related to this short turnaround time, this delivery option shall not be utilized to fill orders for non-emergency needs.
 
 
 
==903.3.17 Ordering Posts==
 
 
 
'''Support.''' Table 903.3.17 contains information on posts.
 
 
 
When ordering pipe posts and stubs, note the size is the inside diameter. When ordering clamps and caps the size is the outside diameter.
 
 
 
Each district is to maintain a supply of signposts, based on average annual usage, for each type of post.
 
 
 
<center>
 
===Table 903.3.17 Posts===
 
 
 
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
 
|+
 
! style="background:#BEBEBE"|Post Type !! style="background:#BEBEBE"|Commodity Code  !! style="background:#BEBEBE"|Description
 
|-
 
|align="center" rowspan="16"|'''U-Channel'''||8013047500|| POST, MEDIUM CHANNEL, #2, 6'
 
|-
 
|width=80|8013047505|| POST, MEDIUM CHANNEL, #2, 6'6"
 
|-
 
|8013047510|| POST, MEDIUM CHANNEL, #2, 8'
 
|-
 
|8013047515|| POST, MEDIUM CHANNEL, #2, 9'
 
|-
 
|8013047520|| POST, MEDIUM CHANNEL, #2, 10'
 
|-
 
|8013047525|| POST, MEDIUM CHANNEL, #2, 12'
 
|-
 
|8013047527|| POST, MEDIUM CHANNEL, #2, 14'
 
|-
 
|8013047528|| POST, MEDIUM CHANNEL, #2, 15'
 
|-
 
|8013047529|| POST, MEDIUM CHANNEL, #2, 16'
 
|-
 
|8013047530|| POST, HEAVY CHANNEL, #3, 6'
 
|-
 
|8013047535|| POST, HEAVY CHANNEL, #3, 9'
 
|-
 
|8013047540|| POST, HEAVY CHANNEL, #3, 10'
 
|-
 
|8013047545|| POST, HEAVY CHANNEL, #3, 12'
 
|-
 
|8013047550|| POST, HEAVY CHANNEL, #3, 14'
 
|-
 
|8013055700|| POST, SIGN, STEEL, R/W POST, 6 FT. 1 LB, STEEL CHANNEL
 
|-
 
|8013055720|| POST, SIGN, STEEL, DELINEATOR POST, 7FT. STEEL CHANNEL
 
|-
 
|align="center" rowspan="22"|'''Pipe'''|| 8013047137 ||POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 10 FT.
 
|-
 
|8013047139|| POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 12 FT
 
|-
 
|8013047141|| POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 14 FT.
 
|-
 
|8013047143|| POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 16 FT.
 
|-
 
|8013047145|| POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 18 FT.
 
|-
 
|8013047147|| POST, SIGN, PIPE, 2-1/2 IN (I.D.) X 20 FT.
 
|-
 
|8013047171|| POST, SIGN, PIPE, 3 IN (I.D.) X 10 FT.
 
|-
 
|8013047172|| POST, SIGN, PIPE, 3 IN (I.D.) X 12 FT.
 
|-
 
|8013047174|| POST, SIGN, PIPE, 3 IN (I.D.) X 14 FT.
 
|-
 
|8013047176|| POST, SIGN, PIPE, 3 IN (I.D.) X 16 FT.
 
|-
 
|8013047178|| POST, SIGN, PIPE, 3 IN (I.D.) X 18 FT
 
|-
 
|8013047180|| POST, SIGN, PIPE, 3 IN (I.D.) X 20 FT.
 
|-
 
|8013047212|| POST, SIGN, PIPE, 4 IN (I.D.) X 12 FT.
 
|-
 
|8013047214||POST, SIGN, PIPE, 4 IN (I.D.) X 14 FT.
 
|-
 
|8013047216|| POST, SIGN, PIPE, 4 IN (I.D.) X 16 FT.
 
|-
 
|8013047218|| POST, SIGN, PIPE, 4 IN (I.D.) X 18 FT.
 
|-
 
|8013047220|| POST, SIGN, PIPE, 4 IN (I.D.) X 20 FT.
 
|-
 
|8013023252|| STUB, SIGN, PIPE, 2-1/2 IN (I.D.) X 4 FT - 3-1/2 IN
 
|-
 
|8013023254|| STUB, SIGN, PIPE, 3 IN (I.D.) X 4 FT - 3-1/2 IN
 
|-
 
|8013023258|| STUB, SIGN, PIPE, 4 IN (I.D.) X 5 FT - 3-1/2 IN
 
|-
 
|8010120294|| BREAKAWAY HARDWARE, SIGN, PIPE, 2-1/2 IN (I.D.) & 3 IN (I.D.)
 
|-
 
|8010120296|| BREAKAWAY HARDWARE, SIGN, PIPE, 4 IN (I.D.)
 
|-
 
|align="center" rowspan="51"|'''Structural/Wide Flange (WF)'''||8013047412|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 12' 0
 
|-
 
|8013047414|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 14' 0
 
|-
 
|8013047416|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 15' 0
 
|-
 
|8013047418|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 16' 0
 
|-
 
|8013047420|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 18' 0
 
|-
 
|8013047422|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 20' 0
 
|-
 
|8013047424|| POST, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 30' 0
 
|-
 
|8013047884|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 14' 0
 
|-
 
|8013047886|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 15' 0
 
|-
 
|8013047888|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 16' 0
 
|-
 
|8013047890|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 17' 0
 
|-
 
|8013047906|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 18' 0
 
|-
 
|8013047908|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 20' 0
 
|-
 
|8013047439|| POST, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 30' 0
 
|-
 
|8013047909|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 18' 0
 
|-
 
|8013047910|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 20' 0
 
|-
 
|8013047911|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 22' 0
 
|-
 
|8013047934|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 24' 0
 
|-
 
|8013047936|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 26' 0
 
|-
 
|8013047940|| POST, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 30' 0
 
|-
 
|8013047912|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 28' 0
 
|-
 
|8013047923|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 18' 0
 
|-
 
|8013047924|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 20' 0
 
|-
 
|8013047925|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 22' 0
 
|-
 
|8013047926|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 26' 0
 
|-
 
|8013047927|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 24' 0
 
|-
 
|8013047929|| POST, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 30' 0
 
|-
 
|8013047913|| POST, SIGN, STRUCTURAL DESIGN #5, W10 X 26 - 25' 0
 
|-
 
|8013047914||POST, SIGN, STRUCTURAL DESIGN #5, W10 X 26 - 40' 0
 
|-
 
|8013047915|| POST, SIGN, STRUCTURAL DESIGN #5, W10 X 26 - 30' 0
 
|-
 
|8010120255|| POST, SIGN, STRUCTURAL DESIGN #6, W12 X 35 - 40' 0
 
|-
 
|8013023388||STUB, SIGN, STRUCTURAL DESIGN #1, W6 X 9 - 3' 0
 
|-
 
|8013023396|| STUB, SIGN, STRUCTURAL DESIGN #2, W6 X 15 - 4' 0
 
|-
 
|8013023416|| STUB, SIGN, STRUCTURAL DESIGN #3, W8 X 18 - 4' 6
 
|-
 
|8013023426||STUB, SIGN, STRUCTURAL DESIGN #4, W10 X 22 - 5' 0
 
|-
 
|8013023436||STUB, SIGN, STRUCTURAL DESIGN #5, W10 X 26 - 5' 0
 
|-
 
|8010120250|| STUB, SIGN, STRUCTURAL DESIGN #6, W12 X 35 - 5' 6
 
|-
 
|8010120260|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #1
 
|-
 
|8010120262|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #2
 
|-
 
|8010120264|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #3
 
|-
 
|8010120266|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #4
 
|-
 
|8010120268|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #5
 
|-
 
|8010120270|| FUSE PLATE, SIGN, STRUCTURAL DESIGN #6
 
|-
 
|8010120275|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #1
 
|-
 
|8010120277|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #2
 
|-
 
|8010120279|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #3
 
|-
 
|8010120281|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #4
 
|-
 
|8010120283|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #5
 
|-
 
|8010120285|| SPLICE PLATE, SIGN, STRUCTURAL DESIGN #6
 
|-
 
|8010120290|| BREAKAWAY HARDWARE, SIGN, STRUCTURAL DESIGN #1, #2, #3
 
|-
 
|8010120292|| BREAKAWAY HARDWARE, SIGN, STRUCTURAL DESIGN #4, #5, #6
 
|-
 
|align="center" rowspan="22"|'''PSST'''||8013047570|| POST, SQUARE, PERFORATED, 2"X10'
 
|-
 
|8013047620|| POST, SQUARE, PERFORATED, 2" X 12'
 
|-
 
|8013047670|| POST, SQUARE, PERFORATED, 2" X 14'
 
|-
 
|8013047672|| POST, SQUARE, PERFORATED, 2" X 16'
 
|-
 
|8013047575|| POST, SQUARE, PERFORATED, 2.5"X10'
 
|-
 
|8013047625|| POST, SQUARE, PERFORATED, 2.5" X 12'
 
|-
 
|8013047675|| POST, SQUARE, PERFORATED, 2.5" X 14'
 
|-
 
|8013047679|| POST, SQUARE, PERFORATED, 2.5" X 16'
 
|-
 
|8010120305|| POST, DOUBLER, SQUARE, PERFORATED, 2.25” X 6’, 12 GAUGE
 
|-
 
|8013047685|| SPLICE, SQUARE, PERFORATED, 1.75"X1'
 
|-
 
|8013023206|| ANCHOR, SQUARE, PERFORATED, 2.25"X 3', 12 GAUGE
 
|-
 
|8013023208|| ANCHOR, SQUARE, PERFORATED, OMNI DIRECTIONAL, 2.25" X 3', 12 GAUGE
 
|-
 
|8013023214|| ANCHOR, HEAVY DUTY, 2.5" x 3', 7 GAUGE
 
|-
 
|8013023210|| ANCHOR, HEAVY DUTY, OMNI DIRECTINAL 2.5" x 3', 7 GAUGE
 
|-
 
|8010120300|| ANCHOR, HEAVY DUTY, 2.5" x 4', 7 GAUGE
 
|-
 
|8013059083|| BOLT, ANCHOR, CORNER 5/16" X 2" ZINC GALVANIZED, GRADE 2 W/NUT MEDIUM
 
|-
 
|8013047689|| SPLICE, SQUARE, PERFORATED, 2.25"X 1', 12 GAUGE
 
|-
 
|8013023230|| ANCHOR, HEAVY DUTY, 3" X 3', 7 GAUGE
 
|-
 
|8010120302|| ANCHOR, HEAVY DUTY, 3" X 4', 7 GAUGE
 
|-
 
|8013023211|| ANCHOR, HEAVY DUTY, OMNI DIRECTIONAL, 3" X 3', 7 GAUGE
 
|-
 
|8013059085|| BOLT, ANCHOR, CORNER 5/16" X 2 .5" ZINC GALVANIZED, GRADE 2 W/NUT LARGE
 
|-
 
|8013059100|| BOLT, ANCHOR, SHOULDER 3/8" X 3.5" ZINC GALVANIZED, GRADE 2 W/NUT (USED FOR ALL HEAVY-DUTY ANCHORS)
 
|}
 
</center>
 
 
 
==903.3.18 Post Storage==
 
 
 
'''Standard.''' Wood posts shall not be painted.
 
 
 
'''Guidance.''' Wood posts should be stacked properly to prevent warping, including bands remaining on the posts until they should be used. Steel posts should be stored so that they do not lie on the ground. Steel posts, if galvanizing becomes chipped or otherwise damaged, are not to be painted with a liquid galvanizing paint.
 
 
 
==903.3.19 Project Contract Signing Field Checks==
 
 
 
'''Support.'''  It is suggested that district traffic personnel, in conjunction with construction and/or design personnel, conduct field checks of project contract signing as soon as the roadway has been roughed-in to the extent that the actual visibility and effectiveness of each sign can be determined.
 
 
 
==903.3.20 Maintenance (MUTCD Section 2A.22)==
 
[[image:903.2.18 Maintenance.jpg|right|250px]]
 
'''Support.'''  The storing methods are in place to prevent damage to the sign sheeting.  Storing signs wet or horizontally will damage the retroreflective elements of the sheeting.  MoDOT has a warranty for the sign sheeting, but improper storage will void the warranty.  
 
 
 
'''Standard.'''  If packaged signs become wet, they shall be unpacked immediately and allowed to dry.  Signs shall always be stored indoors on edge.  New signs shall be stored in a cool, dry area to prevent moisture damage.
 
 
 
'''Guidance.'''  All traffic signs should be kept properly positioned, clean, and legible, and should have adequate retroreflectivity.  Damaged or deteriorated signs should be replaced.
 
 
 
To assure adequate maintenance, a schedule for inspecting (both day and night) and replacing signs should be established.  All employees whose duties require that they travel on the roadways should be encouraged to report any damaged, deteriorated, or obscured signs at the first opportunity.
 
 
 
Weeds, trees, shrubbery, and construction, maintenance and utility materials and equipment should not obscure the face of any sign.
 
 
 
{| style="margin: 1em auto 1em auto"
 
|-
 
|[[image:903.2.18 Flat Sign Storage.jpg|left|175px|thumb|<center>'''Flat sign storage'''</center>]]
 
||[[image:903.2.18 Large Sign Storage.jpg|175px|left|thumb|<center>'''Large sign storage'''</center>]]
 
|}
 
 
 
==903.3.21 Sign Inspection and Inventory==
 
 
 
'''Standard.'''  A sign maintenance program shall be established for all routes within our systems.  All signs on all routes shall be inspected once a year as follows:
 
 
 
A. Even numbered years a daylight inspection shall be performed.
 
 
 
B. Odd numbered years a night inspection shall be performed.
 
 
 
District database information containing sign logs for interstate, primary and supplementary systems shall be submitted to Maintenance office by July 1 of each year.  It is the intention for this Division office to retain only the current year's sign logs.  Each district shall retain copies of previous sign logs.  The sign logs sent to the Highway Safety and Traffic Division as required by the due date list shall be copies of each district's sign logs with the district retaining the master and a backup.
 
 
 
'''Guidance.'''  Appropriate district personnel should perform the inspection of the interstate and primary systems.  The sign inventory process is typically:
 
 
 
A.  The sign inspection log shall include every sign on all routes within our system.
 
 
 
B.  The exact message of those signs classified as guide signs shall be provided on the sign inspection log with no abbreviations.
 
 
 
C.  Signs other than guide signs may be abbreviated. Care should be used in abbreviations that there will be no misunderstanding as to their meaning.
 
 
 
D.  For those signs within an assembly, such as a junction assembly, the log should reflect the total number of signs within that assembly.
 
 
 
E.  Trailblazer signs for LOGO signs should be logged using the corresponding generic service panel (i.e.: Gas LOGO D9-7G, Food LOGO D9-7F, Lodging LOGO D9-7L, Camping LOGO D9-3, Attractions LOGO D9-7a).
 
 
 
F.  Signs requiring maintenance should be noted on the log.
 
 
 
Sign inspections should be performed and recorded as follows:
 
 
 
A.  All signs should be logged if the sign’s face is visible for that direction of travel.
 
 
 
B.  When a sign on an intersecting road with our system is logged, the other system should be identified.
 
 
 
:1.    If possible, identify the [http://www.modot.org/newsandinfo/CountyMaps.htm county road] or city street by name and also note whether the intersecting road is a crossroad or on the right or left.
 
 
 
:2. This data can be noted in parenthesis in the comments section.
 
 
 
:3. Other items which should be noted in the comments section are whether the signs are mounted back-to-back and/or at 90 degrees to another sign.
 
 
 
C.  Slashes should be used to differentiate between lines on a sign.
 
 
 
D.  Arrows should be recorded as follows AH (ahead), LT (left), RT (right), 45LT and 45RT.
 
 
 
E.  Routes must be designated with a prefix in order to efficiently sort the file.
 
 
 
:1.  The designation of "IS" will be used for Interstate Routes, "US" for U.S. Routes, "MO" for Missouri lettered and numbered routes and “BU” for Business Routes.
 
 
 
:2. Lettered prefixes will immediately precede the route designation with no space or dash between the designation and the route.
 
 
 
:3. When the route is a business or spur route, no designation will be necessary.
 
 
 
F.  Signs within an assembly should be numbered from top to bottom and the columns will be lettered from left to right with the first column having no letter, the second column having letter "A" and so on. (See Fig. 903.3.21 Standard Numbering for Route Marker Assemblies)
 
 
 
[[image:Figure 903.2.22.gif|frame|center|thumb|'''Fig. 903.3.21, Standard Numbering for Route Marker Assemblies''']]
 
 
 
G.  The log mile used to record the location of a sign should be the same as the log mile system established for accident data.  
 
 
 
It is recommended an individual should be trained for proper mounting location and sign height, as well as inventory and sign ordering procedures.  This individual would check to see that items marked on sign logs are accomplished within the year.  The number of individuals trained in signing is based on district needs.
 
 
 
Sign quantities should be indicated by commodity code for each sign number within each organization.  This is imperative to enable the inventory to be correctly maintained.
 
 
 
'''Support.'''  The maximum inventory levels for all signs have been determined from the average annual usage for each type of sign.  The maximum inventory represents approximately 1/3 of the average annual usage.  This policy does not apply to signs used for emergency closures and routine maintenance operation traffic control signs.
 
 
 
The route designations used during the log process allow the records to be sorted by route without sorting out additional routes.  For example, when sorting Route 3 without the designation prior to the number, one would also access Routes 35, 350 etc.
 
 
 
Examples of the lettered prefixes for route designations are shown in Table 903.3.21.
 
 
 
<center>
 
===Table 903.3.21 Route Designations===
 
 
 
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
 
|+
 
! style="background:#BEBEBE"|Word Message !! style="background:#BEBEBE"|Standard Abbreviation
 
|-
 
| Interstate||align="center"| IS
 
|-
 
|US Numbered Route||align="center"| US
 
|-
 
|Missouri Numbered Route||align="center"| MO
 
|-
 
|Alternate Route||align="center"| AL
 
|-
 
|Missouri Letter Route||align="center"| RT
 
|-
 
|Business Loop (Interstate Only)||align="center"| LP
 
|-
 
|Business Route||align="center"| BU
 
|-
 
|Spur Route||align="center"| SP
 
|-
 
|Reversible Route||align="center"| RV
 
|-
 
|Outer Road||align="center"| OR
 
|-
 
|City Street||align="center"| CST
 
|-
 
|County Road|| align="center"|CRD
 
|-
 
|Ramp||align="center"| RP
 
|-
 
|Connector for Wye Leg||align="center"| CO
 
|-
 
|Rest Area ||align="center"|RA
 
|-
 
|Weight Station ||align="center"|WS
 
|-
 
|National Forest Service||align="center"| NFS
 
|-
 
|National Park Service||align="center"| NPS
 
|-
 
|Fish Wildlife Service||align="center"| FWS
 
|-
 
|Corp of Engineers||align="center"| COE
 
|-
 
|Department of Defense||align="center"| DOD
 
|-
 
|Alley||align="center"| ALY
 
|-
 
|Private Road||align="center"| PVT
 
|-
 
|Railroad||align="center"| RR
 
|-
 
|Pedestrian Path||align="center"| PED
 
|-
 
|Park Trail||align="center"| PK
 
|}
 
</center>
 
When the route is a business or spur route, no designation will be necessary. The nomenclature is provided in Table 903.3.21.
 
 
 
==903.3.22 Salvaged Signs==
 
 
 
'''History.''' During the operations of MoDOT’s Sign Production Center (SPC), old signs were shipped to the Moberly Correctional Center where they were sorted and stored until the SPC submitted a request.  Once the request was received, the prison would clean and straighten the appropriate sign blanks from the reclaimed inventory and ship to the SPC for production. At the peak, 75% of the sign the SPC produced were on these reclaimed sign blanks.  When sign production was first outsourced, the use of reclaimed sign blanks was investigated; however, the shipping cost to the prison and then to the vendor was cost prohibitive, making the use of reclaimed sign blanks more expensive than the use of new aluminum.  As a result, old signs are now sold for scrap at the end of their service life.
 
 
 
'''Support.'''  All signs, including those that have reached the end of their service life or signs in warehouses which have become obsolete, are state property and must be disposed of as scrap. MoDOT’s policy not to transfer ownership of its signs, other than selling as scrap, makes prosecution for sign theft easy as anyone who is in the possession of one of these signs could not have legally acquired it.  MoDOT does not transfer ownership of its signs, in any condition, to local jurisdictions for liability reasons. 
 
 
 
'''Standard.'''  All signs MoDOT no longer has a use for shall be disposed of by selling them as scrap.  These signs are identified as the property of MoDOT using an ID label on the face of the sign. 
 
 
 
Old signs shall be sold utilizing MoDOT accepted sale practices.  When an eligible bidder is identified and awarded the bid for these materials the GS23 Bill of Sale – Traffic Control Devices shall be executed before material ownership is transferred.  This bill of sale has a legal statement included which specifies any traffic control device purchased can only be utilized as scrap and not used or resold as a functional traffic control device. 
 
 
 
'''Option.'''  Old signs can be sold in large lots sold using individual bids or by utilizing an annual contract where material pickup is achieved on an "on call basis" when a sufficient quantity of signs have been compiled.
 
 
 
'''Standard.'''  If an annual contract for an "on call" pickup is used, the price per pound for aluminum shall be based on the price index for aluminum for the day the material is received.  The use of this price indexing shall be included in the contract language.
 
 
 
==903.3.23 Response to Emergencies==
 
 
 
'''Support.'''  Risk Management has established guidelines concerning the response to replacing signs that have been knocked down or otherwise lost, see Table 903.3.23. 
 
 
 
'''Guidance.'''  The Risk Management Manual should be consulted for the proper procedures to follow.
 
 
 
'''Support.''' Priority ranking are defined as follows:
 
 
 
:'''Priority 1''' – Urgent, respond as soon as possible (day or night, weekends or holidays) suspending other lower priority work if necessary. May represent immediate hazard to the public.
 
 
 
:'''Priority 2''' – Repair should be accomplished as soon as practical during normal working hours, but only after Priority 1 repairs are completed.
 
 
 
:'''Priority 3''' – Repair should be accomplished with higher urgency than routine maintenance.
 
 
 
:'''Priority 4''' – Not urgent, normally considered routine maintenance.
 
<center>
 
===Table 903.3.23 Incident Response Signing Plan===
 
 
 
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 
|+
 
! style="background:#BEBEBE" rowspan="2"|Signs !! style="background:#BEBEBE" colspan="4"|Priority
 
|-
 
! style="background:#BEBEBE"|1!!style="background:#BEBEBE" width=130|2!!style="background:#BEBEBE" width=130|3!!style="background:#BEBEBE" width=130|4
 
|-
 
|Barricades (permanent)|| - || X|| - || -
 
|-
 
|Delineators || - || - || - ||X
 
|-
 
|Freeway/Expressway<sup>1</sup>|| - || X ||- || -
 
|-
 
|Guide<sup>1</sup>|| - ||- || X || -
 
|-
 
|Information<sup>1</sup>|| - ||- || X || -
 
|-
 
|Regulatory<sup>1</sup>|| Critical (i.e. Stop, Yield, Do Not Enter, Wrong Way, One Way)||All others || - || -
 
|-
 
|Warning<sup>1</sup> || - || X|| - || -
 
|-
 
|School<sup>1</sup>|| - ||X || - || -
 
|-
 
|Visibility (weeds, trees, etc.)||Involving Regulatory Signs or Signals ||All others|| - || -
 
|-
 
|Sign Lighting || - ||- || X || -
 
|-
 
|Sign Truss Structure Damage||Creating a Traffic Hazard|| - || Not A Traffic Hazard|| -
 
|-
 
|Lane Closure Notification/ Approval Required<sup>2</sup>|| No||No||Yes|| Yes
 
|-
 
|colspan="5" align="left"|'''Note:''' Priorities are guidelines and may be upgraded if deemed necessary
 
|-
 
|colspan="5" align="left"|<sup>'''1'''</sup> Damage that makes the sign ineffective.
 
|-
 
|colspan="5" align="left"|<sup>'''2'''</sup> NHS routes and all other routes with AADT of 1,700 or greater.
 
|}
 
</center>
 
  
==903.3.24 Median Opening Treatments for Divided Highways with Wide Medians (MUTCD Section 2A.23)==
 
  
'''Guidance.'''  Where divided highways are separated by median widths at the median opening itself of 30 ft. or more, median openings should be signed as two separate intersections.
 
  
  
 
[[Category:903 Highway Signing|903.03]]
 
[[Category:903 Highway Signing|903.03]]

Latest revision as of 07:40, 2 July 2020

903.2 Ground-Mounted Signs.jpg

903.3.1 Ground-Mounted Sign Installation

Forms
Signpost Selection Guide
Printable Signpost Selection Guide for use in the field

Guidance. Signs should be ground-mounted whenever possible unless mounting overhead is justified or required.

Standard. If signs are placed on existing supports, they shall meet other placement criteria contained in this article.

Utility and light poles shall not be used to mount signs as they are either not the property and maintenance responsibility of MoDOT or are not designed to carry the additional wind loading a sign adds to the structure.

Option. In areas with space restrictions, available sign truss columns, signal poles, bridge columns, or other significant MoDOT structures, excluding roadway lighting structures, may be used to mount flat sheet aluminum signs.

903.3.2 Lateral Offset (MUTCD Section 2A.19)

Support. The minimum lateral offset is intended to keep trucks and cars that use the shoulders from striking the signs or supports, while keeping signs and object markers close enough to the roadway to be effective.

Standard. Ground-mounted sign supports shall be crashworthy and meet the latest federal crash standards at the time of installation.

Guidance. The provisions below should be applied unless specifically stated otherwise in the EPG for a particular sign or object marker. For ground-mounted signs, the minimum lateral offset should be 12 ft. from the edge of the travelway. If an existing shoulder is wider than 6 ft., the minimum lateral offset for ground-mounted signs should be 6 ft. from the edge of the shoulder or front face of curb. See figures 903.2.26.1 and 903.2.26.2 which illustrate typical examples of the lateral offset requirements contained in this portion of the article.

Maximum offset will depend on roadway geometrics, profiles, and cross-sections, which all affect the visibility of the sign. Signs are generally to be placed no more than 15 ft. from the edge of shoulder.

Ground-mounted signs placed in a gore only requires a minimum of 2 ft. lateral offset from edges of shoulder, face of barrier walls or guard rail.

For divisional and channelizing islands, a 2 ft. lateral offset should be maintained between the edge of sign and the front face of curb. For islands with restricted width the sign should not extend beyond the curb face.

Option. Deviation from the standard lateral offset may be used if a signs effectiveness and visibility are maintained to account for variations in roadside features. For example, to avoid placing signposts in the flow line of a ditch, avoiding drainage structures, pull boxes or sidewalks.

Option. Lesser lateral offsets may be used in business, commercial or residential areas where limited space is available to place signs due to limited right of way, sidewalks or other restrictions which keep the sign from being installed at the correct offset. In these cases, the edge of the sign may be placed up to, but not beyond the face of the curb making every effort to maximize the offset with the space available.

Guidance. Ground-mounted sign supports should not intrude into the usable width of a sidewalk or other pedestrian facility.

903.3.3 Mounting Height (MUTCD Section 2A.18)

Support. Installing signs at the proper mounting height is critical not only for the sign to be seen and function, but also to the functionality of the breakaway design for each type of sign post. Mounting heights are typically listed as “nominal” as it is critical to keep the signs a minimum distance above the ground, however, signs installed excessively high also have issues, such as:

  • Place signs outside of the drivers line of sight
  • Place signs outside the effective range of vehicle headlights at night making signs less visible
  • Signs mounted too tall are more susceptible to wind resulting in signs being pushed out of plumb or being blown over

903.3.3.1 Mounting Height – U-Channel, Wood, Perforated Square Steel Tube (PSST) and Pipe Posts (MUTCD Section 2A.18)

Support. There are typically two mounting heights for signs on u-channel, wood, PSST and pipe posts, 5 feet and 7 feet. Traditionally, the 5-foot mounting height has been applied to “rural” areas and the 7-foot mounting high applied to “urban” areas or within incorporated city limits. However, the term “urban” has more to do with the conditions the signs are being installed within and less about being located within an incorporated city limit. The purpose of the 7-foot mounting height is to provide clearance for passing bicycle and pedestrian traffic, making the sign more visible over parked vehicles along the roadway and permits improved sight distance to drivers permitting them to see below the sign.

The 7-foot mounting height also applies to all freeway and expressway applications to enhance long distance visibility.

Standard. Standard Plans 903 shall be referenced for specific installation and mounting height details. The details in Standard Plans 903 and this section of the EPG shall apply to all signs unless specifically stated otherwise for a specific sign or object marker elsewhere in the EPG.

The minimum mounting height of a sign shall be measured vertically from the bottom of the sign to the elevation of the near edge of the pavement. Minimum sign mounting heights shall be as follows:

  • Sign located in rural areas – 5 feet,
  • Sign located in urban areas – 7 feet,
  • Signs located on freeways and expressways – 7 feet.

The length of post measured from the bottom of the sign to the ground shall also be a minimum of 5 feet. If the length of any post within a sign assembly measures less than 5 feet from the bottom of the sign to the ground, the minimum sign mounting height shall be increased to achieve the minimum 5-foot post length.

Option. Signs may be installed at 5 feet within the boundaries of incorporated city limits if the all following conditions apply:

  • The sign is located outside of business, commercial or residential areas where there are no high densities of entrances and cross street intersections
  • There is no on street parking
  • There are no sidewalks with bicycle or pedestrian traffic

If a secondary sign is mounted below the primary sign on the same sign post(s), the mounting height for the assembly, measured from the near edge of the pavement to the bottom of the secondary sign, may be 1 foot lower than the minimums listed above.

In cases where signs are located on steep back slopes, it may be advantageous to relocate the sign forward or back from the proposed location to an area that is flatter to avoid a sign being mounted too high.

Guidance. Signs located outside of incorporated city limits that are located in areas having characteristics of an urban area, such as around businesses, heavy residential areas, areas with on street parking and areas with sidewalks which support bicycle and pedestrian traffic, should be installed at 7 feet.

Route marking assemblies consisting of a route sign and auxiliary signs should be treated as a single sign for the purposes of sign mounting height.

Support. Fig. 903.2.26.1 illustrates typical examples of the mounting height requirements contained for signs installed on U-Channel, Wood, PSST and Pipe Posts.

903.3.3.2 Mounting Height – Wide Flange (I-Beam) Posts (MUTCD Section 2A.18)

Support. Installing signs at the proper mounting height is critical not only for the sign to be seen and function, but also to the functionality of the breakaway design. Proper mounting height is more critical for breakaway function on Wide Flange posts compared to all other posts due to the hinge component of this post design. As with the other post types, mounting heights for Wide Flange posts are listed as “nominal” as excessive mounting heights have the same negative effects for these installations as exists with the other post types. Wide Flange post mounting heights are greater than other posts, so in areas with back slopes it is recommended to seek out a flatter location in advance or downstream of the original installation to keep the sign as low as possible.

Minimum mounting heights for Wide Flange post installations are not related to rural or urban classifications, but are directly related to how the breakaway system functions. Standard Plans 903 provides details on the nominal mounting heights on wide flange posts. Key details to focus on are:

  • No wide flange post can be shorter than 7’ 9” measured from the hinge to the top of the stub.
  • The hinge point is always below the lowest sign which is attached to the wide flange post.
  • Nominal mounting heights vary depending if there is one sign mounted on the posts or two.
  • For signs located in areas of back slopes, the minimum mounting height may have to be increased, or the sign installed in a different location, in order to achieve the minimum post length of 7ft. 9 in.

903.3.4 Ground-Mounted Sign Support Selection

Support. The majority of MoDOT signs are installed and supported on one of 5 types of ground-mounted sign supports or sign posts. The selection of sign post is based on many factors, but primarily on the size of sign being installed and the type of roadway the sign is being installed along. There is some overlap in sign post applications; more than one sign post may be applicable to a given installation. The final selection of the post type is based on the attributes needed for a support as discussed in each classification of sign post below.

The number of posts needed to support a sign is primarily based on the width of a sign. Typically, signs 48 inches in width and wider are installed on two or more posts. This requirement is based on two factors, the capacity of the post and the long-term stability of the assembly. A wide sign installed on one post will place a torsional force onto a post and in windy conditions can result in an assembly not staying plumb and, in some cases, an actual failure of the post itself.

Standard. The selection of the proper size of sign post shall be based on the sign selection tools listed below. These tools will specify if a post type has the capability to support the sign in question and then specify what size post is required based on the requirements of the installation. Before the correct size of PSST or Wide Flange post can be selected, the length of the longest post must first be determined. In order to determine this, the offset and mounting height must first be determined.

903.3.4.1 U-Channel Posts

Support. MoDOT utilizes two primary sizes of U-Channel Posts, a 3lb/ft high carbon, rerolled rail steel post for sign installations and a low carbon steel 1lb/ft post for road side delineation.

U-channel posts can be used to support MoDOT’s small signs, such as no parking signs, object markers and chevrons on two lane roadways. U-channel posts are typically not suited to support larger permanent signs as they have limited torsional rigidity and have less ability to hold a larger sign steady in windy conditions. These are typically the most economical posts to use to support smaller signs and given these types of signs tend to be installed closer to the roadway their ability to yield more easily to impacts means they pose less of a damage risk to vehicles. U-channel posts are typically installed by driving the post into the ground without a stub or anchor, however, there is a stub / post installation option available which is detailed in the standard plans.

U-Channel posts are considered breakaway with no additional breakaway devices needing to be added. While there are breakaway devices available for U-channel posts, MoDOT’s use of this type of post for smaller signs typically doesn’t justify their use. A U-channel post’s breakaway is typically a yielding function, meaning as a vehicle impacts the assembly, the post yields and lies down in front of the vehicle so it can pass over the assembly.

Standard. U-channel posts shall be installed in accordance with the details found in Standard Plans 903. Sign post selection tools shall be used to determine sign sizes U-channel posts can support and the number of posts needed.

903.3.4.2 Wood Posts

Support. MoDOT’s specs permit three sizes of wood posts to be used, 4 in. x 4 in., 4 in. x 6 in., or 6 in. x 6 in. MoDOT’s wood posts are pressure treated to promote longer life and resist rot and insect damage. Wood posts were once MoDOT’s primary post to support signs on two lane roadways; however, due to issues with material stability PSST posts have become MoDOT’s standard post.

When used, wood posts are capable of supporting most sign assemblies on two lane roadways, from route marker assemblies, speed limit signs, warning signs and distance and destination signs. The use of a high quality wood post and proper installation is the key to a successful installation.

Guidance. The continued use should take into consideration the special characteristics listed in this section.

Proper installation is also critical for the stability of the sign assembly. The wood post should be placed a minimum of 36 inches into the ground, deeper for larger signs or in areas where the soil is weak or sandy, to keep the sign post plumb. When backfilling the hole, material should be added in lifts, or levels, in order to properly compact the backfill. Loose or fine materials, such as sand, sandy soil or dry concrete mix typically will not provide a long term solid backfill and can result in the post falling out of plumb over time.

MoDOT’s specifications should be followed when purchasing wood sign posts. These specifications address a posts load capacity, breakaway attributes and the compatibility between the pressure treatment chemicals and our aluminum signs and sign hardware.

Option. While the soil originally removed from the hole can be used to back fill around the post other alternatives may be used, such as smaller quarry rock with the crushing fines mixed in, concreted mix or expanding urethane foam.

Support. Wood posts are considered breakaway without an add-on breakaway device; however, some sizes of post do need special preparation. 4 in. x 4 in. wood post are considered breakaway without any special modifications; however, 4 in. x 6 in. and 6 in. x 6 in. posts must be cross drilled at the base to weaken them so they will break away. The size of the holes and where they are drilled is critical to these posts meeting breakaway requirements. The details for these holes are found in the Standard Plans 903, it is important to note these breakaway holes are drilled in the sides of the post, not in the front of the post where the sign is mounted.

Standard. If wood posts are used, the proper size and number of posts shall be determined by using the post selection tools.

Fig. 903.3.4.2, Details for Wood Posts Requiring Breakaway Design

History. One of the earliest issues experienced with wood posts is their tendency to warp and twist, both before and after installation. Keeping a sign plumb and appropriately oriented to the roadway is critical to maintain the sign’s legibility and night time retroreflectivity performance. This aspect of wood posts resulted in significant waste of inventory when the posts warped and twisted before being used and increased work load on signing crews who had to correct warped and twisted posts after installations. Another concern with the use of wood posts was the installation required a hole to be dug, the posts set and property back filled so the sign would remain upright. If soil conditions prohibited a hole being dug deep enough or the back fill not capable for being compacted sufficiently the assembly would fall out of plumb. Along with these installation aspects, a wood post sign assembly can be very heavy, especially when the pressure treated wood is still wet with the pressure treating fluids and this can result in the need for additional people to set the post and/or increased risk of injury setting the post by hand.

Towards the end of MoDOT’s reliance on wood posts a new issue was identified relating to the more environmentally friendly treatment process called ACQ (Ammoniacal Copper Quaternary). ACQ replaced CCA (Chromated Copper Arsenate) for residential applications as CCA had chemical component which were not recommended for routine contact with skin. However, unlike CCA, ACQ (especially early versions) turned out to be very corrosive to metals, especially to aluminum. This corrosive nature requires special fasteners to resist this corrosive effect. Early applications of ACQ in other states realized serious sign corrosion to the point the sign would fall off the post in a matter of a few years. While it appears this has improved, special fasteners with special protective coatings are still recommended for use with ACQ posts. As a result, ACQ posts do not meet MoDOT’s specifications and should not be used to support signs. CCA treated posts are still MoDOT’s standard for wood posts, however, it is not commonly available at local home improvement centers and at many lumber yards. Due to MoDOT’s limited use of this product contract purchasing typically is not economical or possible.

903.3.4.3 Perforated Square Steel Tube Posts (PSST)

Support. MoDOT utilizes two sizes of PSST, 2 in. and 2.5 in., both being made from 12-gauge steel. PSST became MoDOT’s standard post for most sign installation applications on two lane roadways in the early 2000’s, replacing wood posts. PSST usage has since expanded to some applications on freeways and expressways.

Unlike U-channel or Wood posts, PSST utilizes a ground anchor, or footing, in which the post is then inserted. MoDOT has several options in its specifications with respect to ground anchor/foundation systems, the uses of each option is heavily based on the soil conditions in the area of the installation and the direction district operations has chosen based on what they have found to work the best for each of their areas. All MoDOT PSST anchors/footings are a minimum of 36” deep, the anchor/footing types for PSST are:

  • 12 Gauge PSST Anchor – this is the basic anchor for 2 in. PSST posts, a 12-gauge anchor does not exist for 2.5 in. PSST posts.
  • 12 Gauge Omni PSST Anchor – this is a 12-gauge PSST anchor with 4 soil stabilization plates added to the anchor to increase soil surface area to help keep signs plumb in weaker soils and/or in windy areas.
  • 7 Gauge Anchor – this is a heavy wall box tube anchor which is the basic anchor for 2.5 in. PSST posts and an optional heavy anchor for 2 in. PSST posts. This anchor is typically used for 2 in. PSST posts in rocky ground where a 12-gauge anchor may deform when driven. 7 gauge anchors only have holes at the top of the tube. The connection between a 7 gauge anchor and a PSST post is accomplished using two shoulder bolts installed at 90 degree angles to each other.
  • 7 Gauge Omni Anchor – this is a 7-gauge anchor with 4 soil stabilization plates added to the anchor to increase soil surface area to help keep signs plumb in weaker soils and/or in windy areas, available for both 2 in. and 2.5 in. PSST posts.
  • Concrete Footings – In some applications it may be desired to install a concrete footing for PSST, similar to the footings for a Pipe Post or Wide Flange Post. Concrete footings can provide a stronger footing compared to one of the directly driven anchors listed above. A concrete footing may also be required in cases where the ground is too hard or rocky to direct drive an anchor and a hole for the anchor may need to be dug in order to install the anchor. All concrete footing installations use a 7-gauge anchor to provide both a durable foundation and to eliminate concrete from flowing through the holes of a normal 12-gauge PSST anchor.
  • Expanding Urethane Footings – This is an alternate to a concrete footing. This permits the footing and the sign to be installed in one trip compared to concrete, which requires a second trip to allow the concrete to cure. The installation requirements for an expanding foam footing are the same as a concrete footing except for the diameter of the footing, which is smaller. It is important to make sure the expanding foam used meets MoDOT specifications as not all foam products are acceptable to support a breakaway sign.

The connection between the PSST and Anchors also vary based on the anchor gauge:

  • 12-gauge anchor / 12-gauge post - The connection between a 12-gauge anchor and the PSST post is accomplished using a corner bolt. The corner bolt pulls the post into a corner of the anchor and eliminates any slack or play between the post and the anchor.
  • 7-gauge anchor / 12-gauge post - Unlike a 12-gauge anchor and 12-gauge post which telescope together with limited slack or play, the fit between a 7-gauge anchor and 12-gauge PSST post is much looser and the radii of each do not match so a corner bolt will not eliminate the slack or play between these two devices. The corner bolts installed at 90-degree angles corrects this issue; the shoulder of the bolt will pass through the holes in the 7-gauge anchor, but not through the holes in the post. As a result the two bolts push and lock the post in two directions making a solid connection.
  • Add-on breakaway devices – when required/used, the manufacture’s recommendations and hardware (if supplied) need to be used to connect the anchor, breakaway and post together.

Breakaway aspects of PSST are a little more complicated compared to other MoDOT posts, the requirement for an add-on breakaway device heavily depends on the size and number of posts needed to support the sign. It is important to follow the guidance found in the sign post selection tools and MoDOT’s standard plans to determine when an add-on breakaway device is required and when it is not. In applications where add-on breakaway devices are not required/used, PSST breaks away like a U-channel post in a yielding fashion, typically staying attached to the ground and lying down in front of the vehicle so the vehicle can pass over the assembly. However, when an add-on breakaway device is used the breakaway function changes and the assembly is designed to break away from the ground and permit the vehicle to pass under the airborne assembly.

Standard. If PSST posts are used, they shall be either 2 in. or 2.5 in. 12-gauge posts. The size and number of posts, as well as the requirement for add on breakaway devices, shall be determined using the post selection tools. PSST posts shall be installed in accordance with Standard Plans 903.

903.3.4.4 Pipe Posts

Support. MoDOT utilizes three sizes of pipe post, 2 ½ in., 3 in. and 4 in. An important fact to understand is pipe post sizes are based on the inside diameter (I.D.) of the pipe post and not the outside diameter, this is the industry standard for pipe measurement. This is critical in selecting the correct pipe from inventory as well as charging out the correct post to keep your inventory levels correct.

Pipe posts have a similar sign capacity as PSST, even though they would appear to be able to carry a larger sign load due to size and thickness of the steel pipe. While the post themselves are far stronger than PSST, it is the breakaway of the pipe post which primarily controls the sign load capacity of the post. The heavy-duty construction of a pipe post is not specifically related to sign load capacity but is more directly related to the durability of the post. Unlike PSST, which must be replaced after each vehicular impact, pipe posts are constructed with much thicker steel so the sign post can be impacted by a vehicle without being damaged and reinstalled for continued use. There are many pipe posts on our right of way that have been there for two or three generations of signs and are still functional so while they are heavier and more expensive, they are a long term investment and are far more durable.

Pipe posts are used for single and double sign post assemblies to support signs up to 30 sqft. These posts are typically used on freeways and expressways where signs are larger, wind speeds can be higher due to more open right of way and the sign may see larger snow load impact from plows pushing more snow from across multiple lanes to the right side of the roadway. Their resistance to these larger loads is due to their heavier construction, but more importantly to their larger, deeper foundations.

Pipe posts are also the preferred post to support large route assemblies, especially on freeways and expressways. In the past, Wide Flange posts were once used to support these assemblies (and many remain in place) as the design of the post was well suited to attaching a series of backing bars needed to support the assemblies. However, the multi-direction breakaway and high resistance to torsional or twisting forces makes Pipe posts the preferred post over the Wide Flange design.

Pipe posts are designed and fabricated with the breakaway device as part of the post / stub combination; as long as the post and stub breakaway is assembled correctly the post is capable of being impacted from any direction. Details for the assembly of this post system is found in Standard Plans 903, special attention must be paid to the placement of three breakaway bolts, the required and proper placement of all washers within the breakaway and most critically to the proper tightening and torque of the breakaway bolts.

Standard. If Pipe posts are used, they shall be either 2 ½ in., 3 in. or 4 in. in size. The size and number of posts shall be determined using the post selection tools. Pipe posts shall be installed in accordance with Standard Plans 903.

903.3.4.5 Wide Flange (I-Beam) Posts

Support. MoDOT uses 6 sizes of Wide Flange posts, commonly referred to as Design #1, #2, #3, #4, #5 and #6, increasing in size and capacity respectively. Wide Flange posts are typically used to support signs 30 ft2 and larger and are MoDOT’s highest capacity ground-mount sign support. As with Pipe Posts, Wide Flange post are designed to be a more durable post intended to last multiple generations of signs and designed to be able to be impacted by vehicle and then reassembled and reused.

Wide Flange post are designed and used to support large structural signs, signs made using extruded aluminum panels instead of flat sheet aluminum. The cross section of a wide flange post being that of an I-beam permits structure signs to be easily attached to the post using post clips or “dog clamps” instead of using traditional sign bolts. These posts are traditionally used on freeways and expressways only; however, there may be special applications where they may be used on two lane roadways if the size of the sign is too large for other post options.

Wide Flange posts were once the standard to support large route assemblies on freeways and expressways, however, over time two weaknesses were identified that changed this direction, making Pipe posts the better option. The two weaknesses of Wide Flange posts used to support route assemblies are:

  • Safety - Route assemblies many times are installed in and around intersections and in these locations it is theoretically possible some assemblies could be impacted from any direction of travel. Single Wide Flange posts are only breakaway in two directions and are not designed to be breakaway if impacted on either side, just the front and back of the sign. Pipe posts are designed as a multi-breakaway post and can be impacted from any direction making them the better option for these installations.
  • Torsional / Twisting Force Resistance – Although Wide Flange posts are very strong, they do have a limited resistance to twisting moments when installed as a single post installation. In wind prone locations, sign assemblies on a single Wide Flange post can begin to twist in the wind, and if this continues long enough, it can cause the post to fatigue and break off at the base. Pipe posts have an extreme resistance to twisting and can resist much larger torsional forces compared to wide flange posts.

As with Pipe Posts, Wide Flange posts are fabricated with the breakaway system as part of the post / stub assembly. While Wide Flange posts have a breakaway assembly at ground level like Pipe posts, they also require a hinge system located directly below the sign. The hinge system permits the wide flange post (the portion from the ground to the bottom of the sign) to swing up out of the way of a vehicle when impacted without the upper portion of the post and the sign needing to move. This reduces the mass that a vehicle must move when it impacts the post and in return reduces the impact energy to the car.

Unlike all other MoDOT posts, there are minimum post spacing which must be taken into consideration when selecting the correct number and size of post. Wide Flange Posts are much heavier than any other MoDOT post and hitting two of these posts at the same time in most cases would impart too much energy to the vehicle and would not meet minimum breakaway standards. These special considerations are included in Standard Plans 903 which contains all of the fabrication and installation details for Wide Flange Posts, however, due to their critical nature they are also listed here:

  • Wide Flange Post Designs #1 and #2 have no minimum post spacing requirements.
  • Wide Flange Post Designs #1 or #2 shall not be installed in three post configurations supporting signs less than 11 feet width.
  • Wide Flange Post Designs #3, #4, #5 and #6 shall be spaced at least 7 ft. apart.

The post selection tool is designed to utilize two post installations over three post installations to help address minimum post spacing; it also reduces the number of footings which need to be constructed. However, there are some general rules based on sign size used to judge the number post for different size ranges of signs:

  • Signs between 6 ft. and 17 ft. wide will typically be supported on two posts
  • Signs wider than 17 ft. will typically be supported by three posts
  • Signs of any size are not recommended to be installed on one Wide Flange post

Standard. If Wide Flange posts are used, they shall be either a structural #1, #2, #3, #4, #5 or #6 in design. The size and number of posts shall be determined using the post selection tools. Wide Flange posts shall be installed in accordance with Standard Plans 903.

903.3.5 Secondary Sign Supports – Post Extensions

Support. These supports are 3 in. aluminum I-Beam used to attach exit number panels to the top of, or to hang a secondary sign below, structural signs on new installations. Details of these posts are shown in the Standard Plans 903.

Option. There are occasions where modifications and/or additions must be made to existing sign installations where the existing posts are not long enough to support the new sign assembly. In these cases, it is permissible to utilize secondary sign supports to effectively extend the primary sign posts to support signs a maximum of 3 feet taller than the existing primary sign posts.

Secondary sign supports may only be used to allow taller signs to be installed on existing sign posts if the sign posts have the capacity to carry the larger sign based on sign post selection tools.

If a new sign assembly is more than 3 ft taller than the existing primary sign posts, new sign posts shall be installed.

903.3.6 Backing Bars

Support. Backing bars are typically used to support and stiffen wide flat sheet signs mounted on single sign post or to help support the individual signs which make up sign assemblies to form one unified sign assembly. Details for backing bars can be found in Standard Plans 903.

903.3.7 Breakaway Assemblies

Standard. All signposts installed on right of way shall meet federal breakaway standards and MoDOT standards. Sign posts not meeting current standards, but met the standards at the time of their installation, may remain in place until the end of their service life.

Sign trusses and other large sign support structures that are not breakaway shall be protected by acceptable shielding, such as guard rail or barrier wall.

Support. 4 in. x 4 in. wood posts do not need any modification to be breakaway, however 4 in. x 6 in. and 6 in. x 6 in. wood posts will need to be cross drilled to meet breakaway standards. U-Channel posts do not require breakaway modifications if they are direct driven into the ground, however, if the ground stub and slice installation method is used the installation will need to be installed according to the Standard Plans 903 to meet breakaway requirements. PSST will require breakaway devices added in certain applications based on sign and number of posts used for an installation. The sign post selection tools will indicate when a breakaway is required for PSST posts. Pipe and Wide Flange posts have the breakaway devices integrated into the post design.

903.3.8 Sign Orientation (MUTCD Section 2A.20)

Support. The orientation of the face of a sign in relation to the driver and roadway is critical to visibility and legibility, especially at night. The effectiveness of the retroreflective sheeting on a sign can be negatively impacted if the orientation of the sign face is not correct, due to incorrect installation and/or a sign post being damaged and knocked out of alignment.

The orientation of a sign can also help reduce unwanted reflection or glare off of the sign face. The skew angle, shown in Standard Plans 903, is designed to help address this glare issue for tangent sections.

Guidance. Unless otherwise provided in the EPG, signs should be vertically mounted at approximately right angles to the direction of, and facing, the traffic that they are intended to serve, with an approximate 3 degree skew angle away from traffic.

Signs that are placed 30 ft. or more from the pavement edge should have a skew angle that is turned toward the road to improve the effectiveness of the retroreflective sheeting.

Option. While the standard skew angle is 93 degrees, the skew angle may be adjusted to maintain brightness and avoid glare for signs on curved sections of road. On roadways with significant grades, sign faces may be tilted forward or back from vertical position to improve the viewing angle.

903.3.9 Sign Mountings (MUTCD Section 2A.21)

Support. Attaching a sign properly to a sign support is critical in order to properly orient the sign in relation to the driver as well as provide a durable, long life installation.

Standard. Plastic/nylon washers shall be used between the heads of all twist fasteners (such as screws, bolts or nuts) and the sign face to protect the sheeting from the twisting action of the fasteners. Signs shall be attached to each type of sign support in accordance with Standard Plans 903.