903.1 General (MUTCD Chapter 2A)

903.1.1 Function and Purpose of Signs (MUTCD Section 2A.01)

Support. The EPG contains Standards, Guidance, and Options for the signing of all types of highways, and site roadways open to public travel within the right-of-way maintained by MoDOT. The functions of signs are to provide regulations, warnings, and guidance information for road users. Words, symbols, and arrows are used to convey the messages. Signs are not typically used to confirm rules of the road.

Detailed sign requirements are located in the following articles of the EPG:

• EPG 903.2 - Regulatory Signs and Barricades
• EPG 903.3 - Warning Signs and Object Markers
• EPG 903.4 - Guide Signs for Conventional Roads
• EPG 903.5 - Guide Signs for Freeways and Expressways
• EPG 903.6 - Toll Road Signs – Not used on MoDOT facilities
• EPG 903.7 - Preferential and Managed Lane Signs – Not used on MoDOT facilities
• EPG 903.8 - General Information Signs
• EPG 903.9 - General Service Signs
• EPG 903.10 - Specific Service Signs
• EPG 903.11 - Tourist-Oriented Directional Signs
• EPG 903.12 - Changeable Message Signs
• EPG 903.13 - Recreational, Historic Site, and Cultural Interest Area Signs
• EPG 903.14 - Emergency Management Signs – Not used on MoDOT facilities

Definitions and acronyms that are applicable to signs are provided in EPG 911 (MUTCD Section 1C.02).

MoDOT typically will not use signing to confirm rules of the road or state laws. The application of such signing will typically be used when a new law is passed for educational purposes, with the signs remaining in place until the end of their service life and then removed. Some signs may be left in place at strategic locations such as major entry points into the state.

Standard. The decision to install and maintain signs to confirm rules of the road or state laws shall be made by the MoDOT Highway Safety and Traffic Division along with the MoDOT Executive Leadership Team.

903.1.2 Standardization of Application (MUTCD Section 2A.02)

Support. It is recognized that urban traffic conditions differ from those in rural environments, and in many instances signs are applied and located differently. Where pertinent and practical, the EPG sets forth separate recommendations for urban and rural conditions. This generally applies to sign mounting heights.

Guidance. Signs should be used only where justified by engineering judgment or studies, as provided in EPG 911 (MUTCD Section 1D.03).

Results from traffic engineering studies of physical and traffic safety or operational factors should indicate the locations where signs are deemed necessary or desirable.

Roadway geometric design and sign application should be coordinated so that signing can be effectively placed to give the road user any necessary regulatory, warning, guidance, and other information.

Standard. Each standard sign (see first paragraph of EPG 903.1.4) shall be displayed only for the specific purpose as prescribed in the EPG. Before any new highway, site roadway open to public travel (see definition in EPG 911 (MUTCD Section 1C.02)), detour, or temporary route is opened to public travel, all necessary signs shall be in place. Signs required by road conditions or restrictions shall be removed when those conditions cease to exist or the restrictions are withdrawn.

903.1.3 Classification of Signs (MUTCD Section 2A.03)

Standard. Signs shall be defined by their function as follows:

A. Regulatory signs give notice of traffic laws or regulations.

B. Warning signs give notice of a situation that might not be readily apparent.

C. Guide signs show route designations, destinations, directions, distances, services, points of interest, and other geographical, recreational, or cultural information.

Support. Barricades are described in EPG 903.2.60 and 616.11.7.

Object markers are described in EPG 903.3.70.

903.1.4 Design of Signs (MUTCD Section 2A.04)

Support. The EPG shows many standard signs and object markers approved for use on streets, highways, bikeways, and pedestrian crossings. Standard signs and object markers have a standardized design, shape, background, and legend as shown in the EPG.

In the provisions for individual standard signs and object markers, the general appearance of the legend, color, and size are shown in the accompanying tables and illustrations, and are not always detailed in the text.

The MoDOT Highway Safety and Traffic Division maintains design files of standard signs, object markers, alphabets, symbols, and arrows that meet or exceed MUTCD standards and are used to detail, order, and fabricate signs used on MoDOT routes.

The basic requirements of a sign are that it be legible to those for whom it is intended and that it be understandable in time to allow for a proper response. Desirable attributes include:

A. High visibility by day and night; and

B. High legibility (adequately-sized letters, symbols, or arrows, and a short legend for quick comprehension by a road user approaching a sign).

Standardized colors and shapes are specified so that the several classes of traffic signs can be promptly recognized. Simplicity and uniformity in design, position, and application are essential for a sign to be effective.

Standard. The term legend shall include all word messages and symbol and arrow designs that are intended to convey specific meanings.

Uniformity in design shall include shape, color, dimensions, legends, letter style, borders, and illumination or retroreflectivity.

Standardization of these designs does not preclude further improvement by minor modifications to the orientation of symbols (see EPG 903.1.9), width of borders, or layout of word messages, but all shapes and colors shall be as indicated.

All symbols (see EPG 903.1.9) shall be unmistakably similar to, or mirror images of, the adopted symbol signs, all of which are shown in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)). Symbols and colors shall not be modified unless otherwise provided in the EPG. All symbols, colors, or other design features for signs not shown in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) shall be approved by the MoDOT Highway Safety and Traffic Division and shall follow the MUTCD procedures for experimentation and change described in EPG 911 (MUTCD Section 1B.01).

Where a standard word message is applicable, the wording shall be as provided in the EPG.

In situations where word messages are necessary other than those provided in the EPG (see the first Option paragraph below), the signs shall be of the same shape and color as standard signs of the same functional type.

Where the legend of a standard sign is a symbol or a combination of a symbol and words, an alternative word legend shall not be allowed in place of the symbol, except as otherwise provided in the EPG.

Where a standard sign provided in the EPG or the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) is applicable, an alternative legend sign or alternative sign design shall not be allowed in place of the standardized legend or design except as provided in the EPG.

Where a standard sign provided in the EPG or the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) is applicable, but the legend is variable, such as for destination names, an alternative sign design or dimensions shall not be allowed in place of the standardized design for the non-variable elements except as provided in the EPG.

Option. The MoDOT Highway Safety and Traffic Division may develop special word legend signs in situations where engineering judgment determines roadway conditions make it necessary to provide road users with additional regulatory, warning, or guidance information, such as when road users need to be notified of special regulations or warned about a situation that might not be readily apparent. Unlike colors that have not been assigned or symbols that have not been approved for signs, new word legend signs may be used without the need for experimentation.

Support. The message conveyed by some special word legend signs might be unclear to the road user. Although experimentation is not required for such word legends, they might still warrant an evaluation to determine comprehension or possible misinterpretation of the intended message by the road user.

Scanning graphics are graphics designed for scanning by machine, and include bar codes, quick-response (QR) codes or other matrix bar-code formats, or similar graphics.

Standard. Unless otherwise provided in the EPG for a specific sign or as provided in the Option paragraph below, telephone numbers, Internet addresses, e-mail addresses, domain names, uniform resource locators (URL), metadata tags (“hash-tags”), and scanning graphics (see Support paragraph above) for the purpose of obtaining information (other than those for maintenance or inventory purposes per the provisions of the second Standard paragraph below) shall not be displayed on any sign, plaque, sign panel, or changeable message sign.

Option. Internet addresses, e-mail addresses, telephone numbers, scanning graphics, or other graphics for the purpose of conveying information may be displayed on the face of signs, plaques, sign panels, and changeable message signs that are oriented away from or otherwise not readily visible to operators of motor vehicles but rather are intended for viewing only by pedestrians, occupants of parked vehicles, and driving automation systems if approved by the MoDOT Highway Safety and Traffic Division.

Standard. Pictographs (see definition in EPG 911 (MUTCD Section 1C.02)) shall not be displayed on signs except as specifically provided in the EPG for a particular type of sign. Pictographs shall be simple, dignified, and devoid of any advertising and shall not contain any scanning graphics (see first Support paragraph above) for the purpose of conveying information. When used to represent a political jurisdiction (a State, county, or municipal corporation) the pictograph shall be the official designation adopted by the jurisdiction, except as provided otherwise in the EPG. When used to represent any other type of jurisdiction, the pictograph shall be the official designation adopted by the jurisdiction. When used to represent a college or university, the pictograph shall be the official seal adopted by the institution. College or university pictographs shall not include pictorial representations of university or college programs, or athletic mascots.

No items other than official traffic control signs, inventory stickers or decals, sign installation dates, manufacturer name, sign sizes, sign designations, anti-vandalism stickers, inventory or maintenance codes, and maintenance-related scanning graphics shall be mounted on the back of a sign.

Only the MoDOT ID logo shall be displayed on the face of a sign to identify the sign as MoDOT property and define the penalties for tampering with the sign. The MoDOT ID logo shall match the detail and installation location as displayed in Standard Plan 903.02.

903.1.5 Shapes (MUTCD Section 2A.05)

Standard. Particular shapes, as shown in Table 903.1.5, shall be used exclusively for specific signs or a series of signs, unless otherwise provided in the EPG for a particular sign or class of signs.

Table 903.1.5, Use of Sign Shapes

Shape	Signs
Octagon*	Stop (R1-1)**
Equilateral Triangle (downward-pointing)*	Yield (R1-2)**
Circle*	Grade Crossing Advance Warning (W10-1)**
Pentagon (upward-pointing)*	School (S1-1) (squares bottom corners)**
Crossbuck (two rectangles in a perpendicular "X" configuration)*	Grade Crossing (R15-1)**
Diamond	Warning Series
Rectangle (including square)	Regulatory Series Guide Series*** Warning Series
Key: * This shape shall be limited exclusively to the sign(s) indicated. ** This sign shall be exclusively the shape shown. *** Guide series includes general service, specific service, tourist-oriented directional, general information, recreational and cultural interest area, and emergency management signs. Note: Signs with standardized designs shall not be modified to accommodate a different shape except as provided in the EPG.

The Crossbuck is a shape exclusive to the Grade Crossing (R15-1) sign and shall not be obscured by mounting a different shape sign on the back of the Crossbuck (see EPG 913.2.3).

Guidance. Shapes that are exclusive to a particular sign (STOP, YIELD, Railroad Advance, School, Warning, and Crossbuck signs) should not be obscured by another sign mounted on the back of the same assembly protruding or extending beyond the edge of the sign with the exclusive shape. The following methods should be considered in lieu of mounting a sign on the back of another sign that would obscure the exclusive shape of the sign:

A. Install the signs on separate mountings to maintain the exclusive shape.

B. Increase the size of the sign with the exclusive shape and/or decrease the size of the sign mounted behind the sign with the exclusive shape so the sign installed on the back does not obscure its shape.

Where the lateral space available in which to install a standard sign is constrained, such as mounting on a narrow median barrier or adjacent to a retaining wall, the following methods should be considered to maintain the shape of the sign:

A. Angle the sign up to 45 degrees toward the roadway while still maintaining adequate legibility.

B. Install the sign at a different location that still provides adequate advance warning, supplementing the sign with a Distance plaque (see EPG 903.3.60), if appropriate.

C. Reduce the size of the sign, but supplement it with a duplicate sign on the opposite side of the roadway (see EPG 903.1.11).

D. In addition to either angling or reducing the size of the sign, supplement it with a duplicate warning sign and Distance plaque at an upstream location.

E. Mount the sign asymmetrically on the sign support, such as when the support is mounted on a bridge parapet or railing, such that the edge of the sign does not overhang the roadway, shoulder, or other areas used by bicyclists or pedestrians.

Option. Where the shape of the sign cannot be maintained due to lateral constraints, the following methods may be considered:

A. For warning signs or other types of signs displayed in a horizontally-oriented rectangle, the legend may be displayed in a vertically-oriented rectangle.

B. When mounted overhead, the word legend for a standard warning sign may be displayed in a horizontally-oriented rectangle.

Support. Provisions for mounting height of signs that overhang any portion of the traveled way are contained in EPG 903.1.15.

Provisions for lateral offset are contained in EPG 903.1.16.

Standard. Modifications to sign shapes, such as cutting off the left and right points of a diamond, shall not be allowed. This applies to both permanent and temporary traffic control signs.

Option. Where the methods described in the first Guidance paragraph of this article are impracticable, the legend of the warning sign may be displayed in a vertically-oriented rectangle.

903.1.6 Colors (MUTCD Section 2A.06)

Standard. The colors to be used on signs and their specific uses on signs shall be as provided in the applicable articles of the EPG. The color coordinates and values shall be as described in 23 CFR, Part 655, Subpart F, Appendix.

Colors (see EPG 911 (MUTCD Section 1D.05)) shall be consistent across the face of a sign or a sign panel. Color gradients (smooth or defined gradual transitions either within a color or transition to another color) shall not be allowed.

Table 903.1.6, Common Uses of Sign Colors

Type of Sign	Legend								Background
	Black	Green	Red	White	Yellow	Orange	Fluorescent Yellow-Green1	Fluorescent Pink	Black	Blue	Brown	Green	Fluorescent Orange	Red	White	Fluorescent Yellow	Purple	Fluorescent Yellow-Green1	Fluorescent Pink
Regulatory	X		X	X					X					X	X
Prohibitive			X	X2										X2	X
Permissive		X													X
Warning	X															X
Pedestrian	X															X
Bicycle	X															X
Guide				X								X
Interstate Route				X						X				X
State Route	X														X
U.S. Route	X														X
Street Name				X								X
Destination				X								X
Reference Location				X								X
Information				X						X		X
Road User Service				X						X
Recreational				X							X	X
Temporary Traffic Control	X												X
Incident Management	X												X						X
School	X																	X
Changeable Message Signs
Regulatory			X4	X					X
Warning, Pedestrian, Bicycle					X				X
Temporary Traffic Control					X	X			X
Guide				X					X			X3
Motorist Services				X					X	X3
Incident Management					X			X	X
School							X		X
1 MoDOT has conducted research on the use of Fluorescent Yellow-Green for Pedestrian and Bicycle Signs. Research did not indicate any safety benefit, therefore the color is reserved for School signs only. 2 Legend and background color combination for use only as identified for specific signs in the EPG or FHWA's Standard Highway Signs publication. 3 These alternative background colors would be provided by blue or green lighted pixels such that the entire CMS would be lighted, not just the legend. 4 Red is used only for the circle and diagonal or other red elements of a similar static regulatory sign. Notes: The purpose of the information in this table is to provide a general overview of common color combinations. The color combinations and orientations for signs with standardized designs shall not be modified. For signs with unique legends, the shape and color shall be the same as standard signs of the same functional type. The colors shown for changeable message signs are for those with electronic displays.

Support. Common uses of sign colors are shown in Table 903.1.6. Color schemes on specific signs are shown in the illustrations located in each applicable EPG article.

Whenever white is specified in the EPG or in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) as a color, it is understood to include silver-colored retroreflective coatings or elements that reflect white light.

The colors coral and light blue are being reserved for uses that will be determined in the future by the Federal Highway Administration.

Information regarding color coding of destinations on guide signs, including community wayfinding signs, is contained in EPG 903.4.

903.1.7 Dimensions (MUTCD Section 2A.07)

Support. To standardize signing throughout the state highway system, MoDOT has predetermined the sizes for all highway signs; refer to the appropriate EPG article. Larger sizes are designed for use on freeways and expressways, and can also be used in oversized applications to enhance road user safety and convenience on other facilities, especially on multi-lane divided highways and on undivided highways having five or more lanes of traffic and/or high speeds. The intermediate sizes are designed to be used on other highway types. MoDOT does not adopt smaller sized signs for bikeways or other off-road applications as MoDOT typically does not maintain these types of facilities. MoDOT's minimum sign sizes generally exceed the MUTCD minimum sign sizes. The MUTCD minimum sizes in these cases are intended more for low-speed, local jurisdictional roadways and not for state highways. The sign size tables at the beginning of each EPG signing article lists the correct sign sizes for MoDOT applications.

Standard. The sign dimensions prescribed in the sign size tables in the various EPG articles shall be used unless engineering judgment determines that other sizes are appropriate. All sign sizes smaller than the prescribed dimensions shall be approved by the MoDOT Highway Safety and Traffic Division.

Guidance. The sizes shown in the Oversized columns in the various sign size tables in the EPG should be used for those special applications where speed, volume, or other factors result in conditions where increased emphasis, improved recognition, or increased legibility is needed, as determined by engineering judgment or study.

Except as provided in the Standard paragraph below, and where specifically prohibited in the EPG, increases above the minimum prescribed sizes should be used where greater legibility or emphasis is needed. If signs larger than the prescribed sizes are used, the overall sign dimensions will typically be increased in 12-inch increments.

Standard. Where a maximum allowable sign size is prescribed, increases in sign size above the maximum size shall not be allowed.

Where engineering judgment determines that sizes that are different from the minimum prescribed dimensions are appropriate for use, standard shapes and colors shall be used. Standard proportions shall be retained as much as practicable. Any application of size which is different from those given in the EPG shall first be approved by the MoDOT Highway Safety and Traffic Division.

903.1.8 Word Messages (MUTCD Section 2A.08)

Standard. Except as otherwise provided in the EPG, all word messages shall be aligned horizontally across a sign, reading left to right.

Except as provided in EPG 903.1.4, all word messages shall use standard wording as shown in the EPG and in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)).

All sign lettering, numerals, and other characters shall be of the Standard Alphabets as provided in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)), unless otherwise provided in the EPG.

The sign lettering for names of places, streets, and highways shall be composed of a combination of lower-case letters with initial upper-case letters. The sign lettering for other legends shall be composed of upper-case letters, unless otherwise provided in the EPG for a particular sign or type of message.

Except as provided in EPG 903.5, when a mixed-case legend is used, the nominal loop height of the lower-case letters shall be ¾ of the height of the initial upper-case letter.

The unique letter forms for each of the Standard Alphabet series shall not be stretched, compressed, warped, or otherwise manipulated.

Any non-standard or variable sign shall be detailed by the MoDOT Highway Safety and Traffic Division for signs installed by MoDOT forces as well as those installed by contractors on MoDOT projects.

Support. EPG 903.4.3 contains information regarding the acceptable methods of modifying the length of a word for a given letter height and series.

Guidance. Word messages should be as brief as practical to convey a clear, simple meaning, and the lettering should be large enough to provide the necessary legibility distance. A minimum specific ratio of 1 inch of letter height per 30 feet of legibility distance should be used.

Abbreviations (see EPG 911 (MUTCD Section 1D.08)) should be kept to a minimum, except as otherwise prescribed in the EPG.

Word messages should not contain periods, apostrophes, question marks, ampersands, or other punctuation or characters that are not letters, numerals, or hyphens unless necessary to avoid confusion.

Support. Diacritical marks on words or names that are adapted to English are not normally needed on signs for comprehension or navigational purposes.

A legend in a secondary language, in addition to English, may be displayed on the face of signs, plaques, sign panels, and changeable message signs that are oriented away from or otherwise not readily visible to operators of motor vehicles, but rather are intended for viewing only by pedestrians and occupants of parked vehicles.

Guidance. The solidus (slanted line or forward slash) is intended to be used for fractions only and should not be used to separate words on the same line of legend. Instead, a hyphen should be used for this purpose, such as “TRUCKS - BUSES.”

Standard. Fractions shall be displayed with the numerator and denominator diagonally arranged about the solidus. The overall height of the fraction is measured from the top of the numerator to the bottom of the denominator, each of which is vertically aligned with the upper and lower ends of the solidus. The overall height of the fraction shall be determined by the height of the numerals within the fraction, and shall be 1.5 times the height of an individual numeral within the fraction.

Except as otherwise provided in the EPG, distances shall be displayed on signs using fractions of a mile rather than decimals.

Support. The FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)) contains details regarding the layouts of fractions on signs.

Guidance. When initials are used to represent an abbreviation for separate words (such as “U S” for a United States route), the initials should be separated by a space of between ½ and ¾ of the letter height of the initials.

When an Interstate route is displayed in text form instead of using the route shield, a hyphen should be used for clarity, such as “I-70.”

Support. Letter height is expressed in terms of the height of an upper-case letter. For mixed-case legends (those composed of an initial upper-case letter followed by lower-case letters), the height of the lower-case letters is derived from the specified height of the initial upper-case letter based on a prescribed ratio. Letter heights for mixed-case legends might be expressed in terms of both the upper- and lower-case letters, or in terms of the initial upper-case letter alone. When the height of a lower-case letter is specified or determined from the prescribed ratio, the reference is to the nominal loop height of the letter. The term loop height refers to the portion of a lower-case letter that excludes any ascending or descending stems or tails of the letter, such as with the letters “d” or “q.” The nominal loop height is equal to the actual height of a non-rounded lower-case letter whose form does not include ascending or descending stems or tails, such as the letter “x.” The rounded portions of a lower-case letter extend slightly above and below the baselines projected from the top and bottom of such a non-rounded letter so that the appearance of a uniform letter height within a word is achieved. The actual loop height of a rounded lower-case letter is slightly greater than the nominal loop height and this additional height is excluded from the expression of the lower-case letter height.

903.1.9 Symbols (MUTCD Section 2A.09)

Standard. Symbol designs shall in all cases be unmistakably similar to those shown in the EPG and in the FHWA's “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)).

Option. Although most standard symbols are oriented facing left, mirror images of these symbols may be used where the reverse orientation might better convey to road users a direction of movement.

Support. New symbol designs are adopted by the Federal Highway Administration based on research evaluations to determine road user comprehension, sign conspicuity, and sign legibility.

Sometimes a change from word messages to symbols requires significant time for public education and transition. Therefore, the EPG sometimes includes the practice of using educational plaques to accompany new symbol signs.

Guidance. New standard warning or regulatory symbol signs should be accompanied by an educational plaque where engineering judgment determines that the plaque will improve road user comprehension during the transition from word message to symbol signs.

Option. Educational plaques may be left in place as long as they are in serviceable condition.

Standard. A symbol used for a given category of signs (regulatory, warning, or guide) shall not be used for a different category of signs, except as specifically authorized in the EPG.

A recreational and cultural interest area symbol (see EPG 903.13) shall not be used on streets or highways outside of recreational and cultural interest areas.

A recreational and cultural interest area symbol (see EPG 903.13) shall not be used on any regulatory or warning sign on any street, road, or highway.

903.1.10 Sign Borders (MUTCD Section 2A.10)

Standard. Unless otherwise provided, signs shall have a border of the same color as the legend in order to outline their distinctive shape and thereby give them easy recognition and a finished appearance.

The corners of all sign borders shall be rounded, except for STOP signs.

Guidance. A dark border on a light background should be set in from the edge, while a light border on a dark background should extend to the edge of the sign. A border for 30-inch signs with a light background should be from ½ to ¾ inch in width, ½ inch from the edge. For similar signs with a light border, a width of 1 inch should be used. For other sizes, the border width should be of similar proportions, but should not exceed the stroke-width of the major lettering of the sign. On signs exceeding 72 x 120 inches in size, the border should be 2 inches wide. On unusually large signs with oversized letter heights, route shields, or other legend elements, the border should be 2.5 inches wide and should not exceed 3 inches in width. Except for STOP signs and as otherwise provided in EPG 903.5.13, the corners of the sign should be rounded to a radius that is concentric with that of the border.

Support. EPG 903.1.12 contains information regarding the use of light-emitting diode (LED) units within the border of a sign.

903.1.11 Enhanced Conspicuity for Standards Signs (MUTCD Section 2A.11)

Option. Based upon engineering judgment, where the improvement of the conspicuity of a standard regulatory, warning, or guide sign is desired, any of the following methods may be used, as appropriate, to enhance the sign’s conspicuity (see Figure 903.1.11):

A. Increasing the size of a standard regulatory, warning, or guide sign.

B. Dual signing of a standard regulatory, warning, or guide sign by adding a second identical sign on the left-hand side of the roadway at the same location.

C. Adding a fluorescent yellow rectangular header panel above a standard regulatory sign, with the width of the panel corresponding to the width of the standard regulatory sign. A legend of “NOTICE,” “STATE LAW,” or other appropriate text may be added in black letters within the header panel for a period of time determined by engineering judgment.

D. Adding a Warning Beacon (see EPG 902.18.3) to a standard regulatory (other than a STOP, DO NOT ENTER, WRONG WAY, or a Speed Limit sign), warning, or guide sign.

E. Adding a Speed Limit Sign Beacon (see EPG 902.18.4 ) to a standard Speed Limit sign.

F. Adding a Stop Beacon (see EPG 902.18.5) to a STOP, DO NOT ENTER, or WRONG WAY sign.

G. Adding a rectangular rapid-flashing beacon (see EPG 902.12) to a Pedestrian, School, or Trail warning sign at an uncontrolled marked crosswalk.

H. Adding light-emitting diode (LED) units within the symbol, legend, or border of a standard regulatory, warning, or guide sign, as provided in EPG 903.1.12.

I. Adding a strip of retroreflective material to the sign support in accordance with the provisions of the second Standard paragraph below.

J. Using other methods that are specifically allowed for certain signs as described elsewhere in the EPG. The MoDOT Highway Safety and Traffic Division will evaluate any new methods to improve sign conspicuity.

Figure 903.1.11 Examples of Enhanced Conspicuity for Signs

Support. Sign conspicuity improvements can also be achieved by removing non-essential and illegal signs from the right-of-way (see EPG 911 (MUTCD Section 1D.02)), and by relocating signs to provide better spacing. EPG 903.1.20 contains information on excessive use of signs.

Standard. Strobe lights shall not be used to enhance the conspicuity of highway signs.

If a strip of retroreflective material is used on the sign support, it shall be at least 4 inches in width, it shall be placed for the full length of the support from the bottom of the sign and extending down the length of the post, with the bottom of the retroreflective strip not being taller than 2 feet above the edge of the roadway, (see Figure 903.1.11), and its color shall match the background color of the primary sign, except that the color of the strip for the YIELD and DO NOT ENTER signs shall be red. The retroreflective strip shall not display any legend or other information. MoDOT’s standard for this application uses a 4” x 72” aluminum panel with the retroreflective material applied to it where the panel can then be attached to the signpost using the same types of fasteners used to attach signs. These panels are available from MoDOT’s third party sign fabricator. Retroreflective strips shall not be placed on the sign supports below green, blue, or brown guide signs and shall only be placed below regulatory, warning, and school signs, and route marker assemblies.

For a post-mounted sign installation, placing a duplicate sign in the same assembly facing the same direction of traffic shall not be permitted as a method of enhancing conspicuity.

If plaques are used, they shall be installed below the main sign, up to two plaques.

Option. Retroreflective strips may be used to help identify and delineate the location of rural and unlit intersections and expressway crossovers, giving drivers visual cues where these intersections are located in dark nighttime conditions, see EPG 620.6.3 for information regarding this application.

903.1.12 LEDs Used for Conspicuity Enhancement on Standard Signs (MUTCD Section 2A.12)

Support. This article regarding light-emitting diode (LED) units applies to the use of illuminated elements that supplement a sign legend to enhance the conspicuity of the sign.

LED units that are used to illuminate the full sign display, background, or legend are changeable message signs (CMS), which are covered in EPG 903.2, 903.3, 903.12, and 908.

The application of LED units in compliance with the third Standard paragraph below does not create a changeable message sign because the legend of the sign is always displayed when the LED units are not illuminated. Changeable message or blank-out signs whose legends change or extinguish by means of illuminated elements are addressed elsewhere in the EPG.

Approved LED sign manufacturers that are MUTCD compliant and whose products have been evaluated by MoDOT are listed in the MoDOT’s Traffic Approved Products List (APL) found on MoDOT's public website (https://www.modot.org/traffic).

Standard. If LED enhanced signs are used, only those products listed on the Traffic APL shall be permitted.

Option. New products may be considered for the APL, however, before being used they must first be vetted by the MoDOT Highway Safety and Traffic Division and its APL review process. The LED Sign Compliance Checklist can be used to verify if a manufacturer’s LED sign is in compliance with the MUTCD and can be considered for the APL.

Light-emitting diode (LED) units may be used individually within the symbol, legend, or border of a sign to enhance the sign conspicuity and legibility (see EPG 903.1.11).

Except as provided in the sixth Standard paragraph below, LED units may either operate continuously or be actuated.

Standard. Where LED units are used to enhance the conspicuity of a sign, the sign shall otherwise comply with the requirements for retroreflection and illumination for nighttime viewing (see EPG 903.1.21).

Except as provided in the Option and Support paragraphs below, and for changeable message signs, neither individual LEDs nor groups of LEDs shall be placed within the background area of a sign.

The application of LEDs to display sign legends or symbols shall use a maximum pitch of 20 millimeters to cover the stroke width of the letter or symbol.

The LEDs shall not protrude outside the sign border or legend when used in such applications, shall have a maximum diameter of ¼ inch, and shall be the following colors based on the type of sign:

A. White or red, with STOP, YIELD, DO NOT ENTER, or WRONG WAY signs.

B. White, with other regulatory signs.

C. White or yellow, with warning signs.

D. White or green, with guide signs.

E. White, yellow, or orange, with temporary traffic control signs.

F. White or yellow, with pedestrian or bicycle warning signs.

G. White or fluorescent yellow-green, with school area signs.

If flashed, all LED units shall flash simultaneously at a steady rate between 50 and 60 times per minute. All the LED units in a sign legend or border shall be illuminated simultaneously with no sequential (chasing) or variable flash rates (dancing), except as otherwise allowed in the EPG. A cluster of LEDs shall not be used within the border of a sign.

Where used in STOP or YIELD signs, flashing LED units shall operate continuously. Actuation of the LED units shall not be allowed.

Flashing LED units shall not be used within the legend or border of a Speed Limit sign to indicate that the displayed speed limit is in effect.

LED units shall not be used within the legend or border of a sign in conjunction with the phrase WHEN FLASHING in its legend (see Item E in the first paragraph of EPG 902.18.3 for the use of Warning Beacons to indicate when a regulatory or warning message is in effect).

Where LED units are used along the edge of a sign, at least one LED unit shall be placed along each edge of the sign, in addition to one LED unit at each corner of the sign, so that the distinct outline of the sign shape is recognized under nighttime viewing conditions. The LED units along each side of the sign shall be spaced approximately equidistantly. For a circular sign shape, the number of LED units shall clearly form the appearance of a circle and not be perceived as some other shape.

The uniformity of the sign design shall be maintained without any decrease in visibility, legibility, or driver comprehension during either daytime or nighttime conditions. The LED units shall have the capability to be dimmed automatically by a timing mechanism or a device sensitive to ambient light (photoelectric cell) such that the LEDs do not reduce the visibility of the sign legend.

Option. For STOP, YIELD, DO NOT ENTER, and WRONG WAY signs, LEDs may be placed within the border or within one border width within the background of the sign.

Support. EPG 616.4.2 contains information about STOP/SLOW paddles used by flaggers. EPG 908.4.1 contains information about STOP paddles used by adult crossing guards.

Other methods of enhancing the conspicuity of standard signs are described in EPG 903.1.11.

903.1.13 Standardization of Location (MUTCD Section 2A.13)

Support. Standardization of position cannot always be attained in practice. Examples of heights and lateral locations of signs for typical installations are illustrated in Figure 903.1.13.1, and examples of locations for some typical signs at intersections are illustrated in Figure 903.1.13.2 and EPG 616.16.

Examples of advance signing on intersection approaches are illustrated in EPG 616.16. EPG 903.2, 903.3, and 903.4 contain provisions regarding the application of regulatory, warning, and conventional guide signs, respectively.

Figure 903.1.13.1 Examples of Locations for Some Typical Signs at Intersections

Figure 903.1.13.2 Examples of Locations for Some Typical Signs at Intersections

Standard. Signs requiring separate decisions by the road user shall be spaced sufficiently far apart for the appropriate decisions to be made.

Guidance. One of the factors considered when determining the appropriate spacing of signs should be the posted or 85th percentile speed.

Mainline signs on freeways and expressways should be visible a minimum of 800 feet and signs on conventional roads should be visible a minimum of 200 feet (minimum sign spacing in EPG 903.4 and EPG 903.5. These distances should be considered when determining spacing between signs and when evaluating sign legibility during sign inspections. When these minimum sign spacing distances are not achievable, engineering judgement should be used to determine if the sign can be relocated to improve visibility, provide advance signing or determine if a reduced sign spacing distance is appropriate.

Except as provided in the third Guidance paragraph below, signs should be located on the right-hand side of the roadway where they are easily recognized and understood by road users. Signs in other locations should be considered only as supplementary to signs in the normal locations, except as otherwise provided in the EPG.

Signs should be individually installed on separate posts or mountings except where:

A. One sign supplements another;

B. Route or directional signs are grouped to clarify information to motorists;

C. Regulatory signs that do not conflict with each other are grouped, such as Turn Prohibition signs posted with ONE WAY signs or a parking regulation sign posted with a Speed Limit sign; or

D. Street Name signs are posted with a STOP or YIELD sign.

Signs should be located so that they:

A. When post mounted, are installed on a breakaway assembly, regardless of where they are located on right-of-way,

B. Optimize nighttime visibility,

C. Minimize the effects of mud splatter and debris,

D. Do not obscure each other,

E. Do not obscure the sight distance to approaching vehicles on the major street for drivers who are stopped on minor-street approaches, and

F. Are not hidden from view.

Except for STOP, YIELD, DO NOT ENTER, and WRONG WAY signs, or as otherwise provided in the EPG, where a sign on a one-way roadway indicates an action intended exclusively or primarily for a road user in the left-hand lane or at the left-hand side of that roadway, such as LEFT LANE MUST TURN LEFT (R3-7) or LEFT LANE ENDS (W9-1), the sign should be located on the left-hand side of the roadway. In the case of a divided road, the sign should be located in the median.

Option. Signs located on the left-hand side of a one-way roadway or in the median of a divided road, in accordance with the Guidance paragraph above, may be supplemented by an identical sign located on the right-hand side of the roadway.

Support. The clear zone (see definition in EPG 911 (MUTCD Section 1C.02)) is the total roadside border area, starting at the edge of the traveled way, available for an errant driver to stop or regain control of a vehicle. The width of the clear zone is dependent upon traffic volumes, speeds, and roadside geometry. Additional information can be found in the “Roadside Design Guide,” 4th Edition, 2011, AASHTO. Based on the Roadside Design Guide, the clear zone only accounts for 80% of vehicles leaving the roadway, leaving 20% traveling outside the clear zone, this is the reason all MoDOT signs are required to be on breakaway sign supports.

Guidance. With the increase in traffic volumes and the need to provide road users regulatory, warning, and guidance information, an order of priority for sign installation should be established.

Support. An order of priority is especially critical where space is limited for sign installation and there is a demand for several different types of signs. Overloading road users with too much information is not desirable. Priority according to type of sign will depend on the specific situation and conditions of the site at which the signs are to be installed. For example, in the vicinity of an exit ramp, guide signs and warning signs for the exit ramp might take precedence over supplemental guide signs or a mainline Speed Limit sign where there is no change in the speed zone.

Guidance. Because regulatory and warning information is typically more critical to the road user than guidance information, regulatory and warning signing whose locations are critical should be displayed rather than guide signing in cases where conflicts occur. In such cases, the guide sign should be relocated to another appropriate location where it will still be effective. In other cases, such as at a decision point, the guide sign should take precedence over other signs whose locations are not as critical to an immediate decision or action necessary by the road user. In all cases, careful attention should be given to minimizing sign clutter (see EPG 903.1.20). Community wayfinding and acknowledgment guide signs should have a lower priority as to placement than other guide signs. Signs conveying information of a less-critical nature should be moved to less-critical locations or omitted.

Option. Under some circumstances, such as on curves to the right, signs may be placed on median islands or on the left-hand side of the road. A supplementary sign located on the left-hand side of the roadway may be used on a multi-lane road where traffic in a lane to the right might obstruct the view to the right.

Guidance. In urban areas where crosswalks exist, signs should not be placed within 4 feet in advance of the crosswalk (see Drawing D in Figure 903.1.13.2).

903.1.14 Overhead Sign Installation (MUTCD Section 2A.14)

Standard. Overhead sign installations shall be limited to MoDOT regulatory, warning, and guide sign installations, unless otherwise specified in the EPG. Supplemental signs or aesthetic messages shall not be displayed on overhead structures, which also apply to structures constructed and installed by another jurisdiction over a state route. Supplemental signs or aesthetic messages include, but are not limited to Welcome To signs, Welcome To monuments, and Community Wayfinding signs.

Guidance. Overhead signs should be used on freeways and expressways, at locations where some degree of lane-use control is desirable, and at locations where space is not available at the roadside. It is recommended that justification be provided when mounting signs overhead.

Support. The operational requirements of the present highway system are such that overhead signs have value at many locations. The factors to be considered for the installation of overhead sign displays are not definable in specific numerical terms. In some cases, overhead mounting of a sign might be required by other provisions of the EPG.

MoDOT has established the following general criteria for the use of overhead signs on the state highway system:

Standard. Overhead signs shall be used in the following applications:

A. EXIT ONLY lane drops,

B. Complex interchange design, including, but not limited to:

1. Directional ramps, and

2. Ramp splits

C. Three or more lanes in each direction in urban areas,

D. Closely-spaced interchanges,

E. Multi-lane exits,

F. Consistency of sign message location through a series of interchanges,

G. Junction of two freeways, and

H. Complex intersection guide signs, including, but not limited to:

1. Multi-lane roundabouts,

2. Diverging Diamond Interchanges, and

3. Single Point Urban Interchanges.

Guidance. Overhead signs should be used in the following applications:

A. Reduction of basic lanes in a LANE ENDS application and

B. Left-side exit ramps.

Option. Overhead signs may be used in the following applications:

A. Insufficient space for post-mounted signs,

B. Restricted sight distance,

C. Traffic volume at or near capacity,

D. Large percentage of trucks,

E. In urban areas with ambient light issues which obscure the visibility of the ground mounted sign,

F. Locations where there is a history of crashes with a ground-mounted sign, and

G. High-speed traffic.

Over-crossing structures may be used to support overhead signs.

Support. Under some circumstances, the use of over-crossing structures as sign supports might be the only practical solution that will provide adequate viewing distance. The use of such structures as sign supports might eliminate the need for the foundations and sign supports along the roadside.

903.1.15 Mounting Height (MUTCD Section 2A.15)

Standard. The provisions of this article shall apply unless specifically stated otherwise for a particular sign or object marker elsewhere in the EPG.

Support. Mounting heights in the EPG and in Standard Plan 903.03 are nominal dimensions, meaning these dimensions represent the minimum mounting height, as well as the maximum mounting heights unless otherwise stated. The mounting height, measured from the roadway surface to the bottom of the sign, is only increased in order to meet the minimum distance requirements from the bottom of the sign to the ground directly below the sign. Minimum mounting heights ensure the installations meet breakaway standards as well as placing the signs at the appropriate level for visibility. Installing signs taller than these nominal dimensions will move the signs outside the driver’s normal line of sight negatively affecting the signs legibility and visibility.

In addition to the provisions of this article, information affecting the minimum mounting height of signs as a function of crash performance can be found in the “Roadside Design Guide,” 4th Edition, 2011, AASHTO.

Standard. In rural areas, 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 shall be 5 feet (see Figure 903.1.13.1).

In business, commercial, or residential areas where parking, bicyclist, or pedestrian movements are likely to occur, or where the view of the sign might be obstructed, 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 traveled way, of signs installed at the side of the road shall be 7 feet (see Figure 903.1.13.1).

Option. The height to the bottom of a secondary sign mounted below another sign may be 1 foot less than the height specified in the Standard paragraphs above.

Standard. The minimum height of signs, measured vertically from the bottom of the sign to the sidewalk shall be 7 feet.

If the bottom of a secondary sign that is mounted below another sign is mounted lower than 7 feet above a pedestrian sidewalk or pathway (see EPG 616.3.2), the secondary sign shall not project more than 4 inches into the pedestrian facility.

Support. EPG 914.1.2 contains provisions for the minimum mounting height of signs on shared-use paths.

Standard. All sign installations shall meet the installation, mounting height and lateral offset of MoDOT specifications for the type of signs support being used, see Standard Plan 903.03.

Option. A route sign assembly (see Figures 903.4.25.1 through 903.4.25.3) consisting of a route sign and auxiliary signs may be treated as a single sign for the purposes of this article.

The mounting height may be adjusted when supports are located near the edge of the right-of-way on a steep backslope in order to avoid the sometimes less desirable alternative of placing the sign closer to the roadway.

Standard. Signs that are post-mounted on a median barrier shall not overhang any portion of the traveled way.

New overhead sign installations shall provide a vertical clearance of not less than 18 feet from the highest point of pavement or shoulder (including mountable curbs located within the shoulder limits) to the lowest point of the sign, light fixture, or sign bridge over the entire width of the pavement and shoulders, except where the structure on which the overhead signs are to be mounted or other structures along the roadway near the sign structure have a lesser vertical clearance. No overhead sign installations shall have a mounting height that is lower than 17 feet.

Option. If the vertical clearance of other structures along the roadway near the sign structure is less than 16 feet, the vertical clearance to an overhead sign structure or support may be as low as 1 foot higher than the vertical clearance of the other structures in order to improve the visibility of the overhead signs.

In special cases the clearance to overhead signs may be reduced if necessary because of substandard dimensions in tunnels and other major structures such as double-deck bridges.

Signs may be raised above the standard vertical clearance to improve visibility and avoid other obstructions such as signal equipment.

Guidance. While a maximum mounting height for signs is generally not prescribed in the EPG, the nominal mounting heights should be adhered to, ensuring that signs are not mounted at such a height as to be out of the road user’s normal field of vision (see the second paragraph of this article and the third paragraph of EPG 911 (MUTCD Section 1D.09)), especially in urban settings where signs are mounted on traffic signal or light poles.

Support. Figure 903.1.13.1 illustrates some examples of the mounting height requirements contained in this article.

See EPG 903.17.4 for information regarding vertical clearances for overhead signs.

903.1.16 Lateral Offset (MUTCD Section 2A.16)

Standard. For overhead sign supports, the minimum lateral offset from the edge of the shoulder (or if no shoulder exists, from the edge of the pavement) to the near edge of overhead sign supports (cantilever or sign bridges) shall be 6 feet. Overhead sign supports shall have a barrier or crash cushion to shield them if they are within the right-of-way.

See EPG 903.17.3 for information regarding lateral offset of overhead sign supports.

Post-mounted sign and object marker supports shall be crashworthy (see EPG 911 (MUTCD Section 1D.11)) if within the right-of-way.

Guidance. For post-mounted signs, the minimum lateral offset should be 12 feet from the edge of the traveled way. If a shoulder wider than 6 feet exists, the minimum lateral offset for post-mounted signs should be 6 feet from the edge of the shoulder.

Supports for signs mounted laterally behind a longitudinal barrier should be placed so that the near edge of the support is located beyond the deflection distance of the longitudinal barrier and the edge of the sign does not extend beyond the face of the barrier towards traffic.

Support. The minimum lateral offset requirements for object markers are provided in EPG 903.3.

The minimum lateral offset is intended to keep trucks and cars that use the shoulders from striking the signs or supports. The minimum lateral offset requirements do not supersede the requirement for crashworthiness (see the second Standard paragraph of this article) if the sign is located within the right-of-way.

Guidance. All supports should be located as far as practical from the edge of the shoulder. Advantage should be taken to place signs behind existing roadside barriers, on over-crossing structures, or other locations that minimize the exposure of the traffic to sign supports.

Option. Lesser lateral offsets may be used on connecting roadways or ramps at interchanges, but not less than 6 feet from the edge of the traveled way.

On conventional roads in areas where it is impractical to locate a sign with the lateral offset prescribed by this article because of roadside features such as terrain or vegetation, a lateral offset of at least 2 feet may be used.

A lateral offset of at least 1 foot 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. Overhead sign supports and post-mounted sign and object marker supports should not obstruct the sidewalk or the pedestrian access route such that less than 4 feet of clear space is available.

Support. Guidance for maintaining sign shape in laterally-constrained conditions is described in EPG 903.1.5.

Figure 903.1.13.1 and 903.1.13.2 illustrate some examples of the lateral offset requirements contained in this article.

903.1.17 Orientation (MUTCD Section 2A.17)

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.

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. 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.

903.1.18 Posts and Mountings (MUTCD Section 2A.18)

Standard. Sign posts, 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.

Support. See Standard Plan 903.03 for additional information regarding posts and mounting. The Standard Plans are compliant with the latest edition of AASHTO’s “Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals.”

Option. Where permitted, signs may be placed on existing supports used for other purposes, such as highway traffic signal supports or overhead sign supports. This does not include utility poles or light poles.

Support. EPG 903.1.11 contains criteria for enhanced conspicuity of standard signs.

EPG 903.1.15 and 903.1.16 contain lateral and height placement criteria for signs placed on existing supports.

Standard. If mounted to the sign support, equipment for powering electronic components of a sign, including solar panels, the sign support shall be a traffic signal pedestal pole with a breakaway base so as to not to compromise the crashworthy performance of the sign installation (see EPG 911 (MUTCD Section 1D.11)). Such equipment shall be mounted so as not to obscure the shape of the sign. Any wiring installed in the breakaway base shall include appropriate breakaway fuse connectors.

903.1.19 Maintenance (MUTCD Section 2A.19)

Guidance. Maintenance activities should consider proper position, cleanliness, legibility, and daytime and nighttime visibility (see EPG 903.1.21 and 903.1.22). Damaged or deteriorated signs or object markers should be replaced.

To assure adequate maintenance, a schedule for inspecting (at night), trimming vegetation, and replacing signs and object markers should be established. Employees of highway, law enforcement, and other public agencies whose duties require that they travel on the roadways should be encouraged to report any damaged, deteriorated, or obscured signs or object markers at the first opportunity. While MoDOT’s sign maintenance program relies on nighttime inspections, random daytime inspections are encouraged to identify needs between scheduled nighttime inspections.

Steps should be taken to see that weeds, trees, shrubbery, and construction, maintenance, and utility materials and equipment do not obscure the face of any sign or object marker.

A regular schedule of replacement of lighting elements for illuminated signs should be maintained.

Support. See EPG 903.20.4 for additional information related to sign inspection.

903.1.20 Excessive Use of Signs (MUTCD Section 2A.20)

Guidance. Signs should be used and located judiciously, minimizing their proliferation in order to maintain their effectiveness. Regulatory and warning signs should be used conservatively because these signs, if used to excess, tend to lose their effectiveness. Route signs and directional guide signs for primary routes and destinations should be used frequently at strategic locations because their use promotes efficient operations by keeping road users informed of their location. In all cases, however, sign clutter (see the Support paragraph below) should be avoided and minimized as much as practicable.

Support. Sign clutter is the proliferation of sign installations or assemblies along the roadway or roadside, either separately or grouped, to such an extent that adequate spacing between installations necessary for orderly processing of the sign messages by the driver cannot be achieved. Sign clutter can reduce the effectiveness of one or more signs in a sequence of signs.

The basic role of traffic control devices is to provide only as much information to the road user as necessary to promote the safe and efficient operation of streets and highways. Sign clutter can result from the overuse of MUTCD-compliant signs and or signs that display information unrelated to traffic operation, navigation, or transportation information. Examples of such signs would include, but are not limited to, those displaying the birthplace or home of a noted person, local sports team accomplishments, population information, and self-described qualities of a community such as “friendly” or “open for business.”

Guidance. Signs and other traffic control devices should be installed and maintained from a systematic standpoint rather than individually. When a new sign is installed, the existing signs in the vicinity should be considered for replacement, relocation, or removal as a result of the new sign that is installed. Existing systems of signs should be reviewed periodically for evidence of sign clutter and adjustments should be made accordingly.

Support. EPG 903.1.13 contains information regarding an order of priority for signs where available spacing along the roadway is limited.

903.1.21 Retroreflection and Illumination (MUTCD Section 2A.21)

Support. There are many materials currently available for retroreflection and various methods currently available for the illumination of signs and object markers. New materials and methods continue to emerge. New materials and methods can be used as long as the signs and object markers meet the standard requirements for color, both by day and by night.

This article applies to visibility of signs at night or in low-light or adverse weather conditions, whose legends are otherwise visible under typical daytime viewing conditions.

Standard. All traffic control signs on MoDOT right-of-way shall be retroreflective to show the same shape and similar color by both day and night, unless otherwise provided in the EPG for a particular sign or group of signs.

Where the color black is specified for the legend or background of a sign, an opaque and non-retroreflective material shall be used.

The requirements for sign illumination shall not be considered to be satisfied by street or highway lighting.

In special conditions when illuminated signs are permitted to be used per the EPG, sign symbols, word messages, and backgrounds shall be illuminated by a light behind the sign face through a translucent material.

Retroreflection of sign elements shall be accomplished by the means shown in Table 903.1.21.

Table 903.1.21, Retroreflection of Sign Elements

Means of Retroreflection	Sign Element
A material that has a smooth, sealed outer surface over a microstructure that reflects light	Symbol Word message Border Background
Note: Illuminated signs are not used by MoDOT. Cities and counties may use illuminated street name signs if a maintenance agreement is in place.

Guidance. Overhead sign installations should not be illuminated unless an engineering study shows a need for illumination, e.g. fog prone areas.

Support. Information regarding the use of retroreflective material on the sign support is contained in EPG 903.1.11.

Information regarding MoDOT sheeting types is contained in EPG 903.16.3.

903.1.22 Maintaining Minimum Retroreflectivity (MUTCD Section 2A.22)

Support. Retroreflectivity is one of several factors associated with maintaining nighttime sign visibility (see EPG 903.1.21).

Standard. MoDOT shall use an assessment or management method that is designed to maintain sign retroreflectivity at or above the minimum levels in Table 903.1.22. Local jurisdictions who maintain sections of state routes and the signs on those sections under maintenance agreements shall maintain those signs in accordance with one of the MUTCD assessment methods.

Table 903.1.22, Minimum Maintained Retroreflectivity Levels

Sign Color	Beaded Sheeting Type (ASTM D4956)			Prismatic Sheeting	Additional Criteria
	I	II	III
White on Green	W*; G ≥ 7	W*; G ≥ 15	W*; G ≥ 25	W ≥ 250; G ≥ 25	Overhead
	W*; G ≥ 7	W ≥ 120; G ≥ 15			Post-mounted
White on Blue	W*; B ≥ 3	W*; B ≥ 5	W*; B ≥ 12	W ≥ 250; B ≥ 12	Overhead
	W*; B ≥ 3	W ≥ 120; B ≥ 7			Post-mounted
White on Brown	W*; Br ≥ 1	W*; Br ≥ 5	W*; Br ≥ 10	W ≥ 350; Br ≥ 10	Overhead
	W*; Br ≥ 1	W ≥ 150; B ≥ 5			Post-mounted
Black on Yellow or Black on Orange	Y*; O*	Y ≥ 50; O ≥ 50			2
	Y*; O*	Y ≥ 75; O ≥ 75			3
White on Red	W ≥ 35; R ≥ 7				4
Black on White	W ≥ 50				-
1 The minimum maintained retroreflectivity levels shown in this table are in units of cd/Ix/m2 measured at an observation angle of 0.2° and an entrance angle of -4.0°. 2 For word legend and fine symbol signs measuring at least 48 inches and for all sizes of bold symbol signs. 3For word legend and fine symbol signs measuring less than 48 inches. 4 Minimum sign contrast ratio ≥ 3:1 (white retroreflectivity ÷ red retroreflectivity). *This sheeting type shall not be used for this color for this application.
Bold Symbol Signs
W1-1,2 - Turn and Curve W1-3,4 - Reverse Turn and Curve W1-5 - Winding Road W1-6,7 - Large Arrow W1-8 - Chevron W1-10 - Intersection in Curve W1-11 - Hairpin Curve W1-15 - 270 Degree Loop W2-1 - Cross Road W2-2,3 - Side Road W2-4,5 - T and Y Intersection W2-6 - Circular Intersection W2-7,8 - Double Side Roads W3-1 - Stop Ahead W3-2 - Yield Ahead W3-3 - Signal Ahead W4-1 - Merge W4-2 - Lane Ends W4-3 - Added Lane W4-5 - Entering Roadway Merge W4-6 - Entering Roadway Added Lane W6-1,2 - Divided Highway Begins and Ends W6-3 - Two-Way Traffic W10-1,2,3,4,11,12 - Grade Crossing Advance Warning W11-2 - Pedestrian Crossing W11-5 - Farm Equipment W11-7 - Equestrian Crossing W11-10 - Truck Crossing W12-1 - Double Arrow W16-5P,6P,7P - Pointing Arrow Plaques W20-7 - Flagger W21-1 - Worker
Fine Symbol Signs (symbol signs not listed as bold symbol signs)
Special Cases W3-1 - Stop Ahead: Red retroreflectivity ≥ 7 W3-2 - Yield Ahead: Red retroreflectivity ≥ 7; White retroreflectivity ≥ 35 W3-3 - Signal Ahead: Red retroreflectivity ≥ 7; Green retroreflectivity ≥ 35 W3-5 - Speed Reduction: White retroreflectivity ≥ 50 For non-diamond shaped signs, such as W14-3 (No Passing Zone), WP-4P (Cross Traffic Does Not Stop), or W13-1P,2,3,6,7 (Speed Advisory Signs), use the largest sign dimension to determine the proper minimum retroreflectivity level.
Note: All MoDOT signs shall be fabricated as retroreflective for durability and longevity

Support. Compliance with the Standard in the paragraph above is achieved by having a method in place and using the method to maintain the minimum levels established in Table 903.1.22. Provided that an assessment or management method is being used, MoDOT would be in compliance with the Standard in the paragraph above even if there are some individual signs that do not meet the minimum retroreflectivity levels at a particular point in time.

MoDOT has a sign inspection process to maintain sign retroreflectivity at or above the minimum levels. See EPG 903.20.4 for additional information related to sign inspection.

903.1.23 Median Opening Treatments for Divided Highways (MUTCD Section 2A.23)

Guidance. A divided highway crossing should be signed and marked as separate intersections when both of the following conditions are present:

A. The paths of opposing left turns from the divided highway cross each other (see Figure 903.1.23), and

B. There is adequate storage in the interior approaches for the design vehicles expected to cross the divided highway.

If either one or both of the conditions in the Guidance paragraph above do not exist, the divided highway crossing should be signed and marked as a single intersection.

Figure 903.1.23 Intersection Configuration at a Divided Highway Crossing

At the crossing of two divided highways, engineering judgment should be used to determine the number of separate intersections.

Support. Divided highway crossings with median widths 150 feet or greater might function as two intersections depending upon the interaction of the opposing left-turn vehicle paths and the available interior storage in the median for a crossing vehicle. Other factors that could determine whether a divided highway crossing is operating as one or two intersections include:

A. The geometric design of the divided highway crossing,

B. The use of positive offset mainline left-turn lanes,

C. The length of the median opening (as measured parallel to the center line of the divided highway),

D. The geometric design of the median noses,

E. Other roadway geometric considerations such as a skewed side street approach or a variable median width,

F. Intersection sight distance,

G. The physical characteristics of the design vehicle, and

H. The observed prevailing driver behavior with regard to opposing left-turn path interaction.

903.1.24 Priority Order of Signs

Standard. The order classification of signs shall be defined as follows (refer to Figure 903.1.24):

1. First Order Signing. Signs that are installed in advance of the closest intersection or interchange where motorists turn off of the state highway system to arrive at the desired traffic generator or site. First order signing will always be on state right-of-way.
2. Second Order Signing. Signs that are installed in advance of the intersection or interchange where motorists turn to access the highway where the first order signing is provided. Second order signing will always be on state right-of-way and shall require the use of first order signing on state right-of-way.
3. Third Order Signing. Signs that are installed in advance of the intersection or interchange where motorists turn to access the highway where the second order signing is provided. Third order signing will always be on state right-of-way and shall require the use of first order and second order signing on state right-of-way.

Figure 903.1.24 Sign Order Classification

Support. In general, as the “order” of signing increases, the functional classification of road stays the same or increases. For example, if first order signing is on a four-lane U.S. route, second order signing should be on another U.S. route, expressway, or a freeway. In this example case, second order signing should not be placed on a two-lane lettered route.