616.6 Temporary Traffic Control Zone Signs - General (MUTCD Chapter 6F)

616.6.1 General Characteristics of TTC Zone Signs (MUTCD Section 6F.01)

Support. TTC zone signs convey both general and specific messages by means of words, symbols, and/or arrows and have the same three categories as all road user signs: regulatory, warning, and guide.

Guidance. Where the color orange is required, the fluorescent orange color should also be used.

Support. The fluorescent version of orange provides higher conspicuity than standard orange, especially during twilight.

Option. Flashing beacons (see EPG 902.18) may be used in conjunction with signs.

Standard. When flashing beacons are used in conjunction with a sign, they shall not block the sign face.

Support. Work zone warning signs are typically 48 in. x 48 in., diamond-shaped, black on fluorescent orange signs with Type 9 or 11 sheeting. Work zone regulatory signs are identical to permanent regulatory signs with Type 4 sheeting. Work zone guide signs are generally rectangular in shape and have a black legend and border on a fluorescent orange background with Type 9 or 11 sheeting; but can come in different sizes, shapes, colors and sheeting depending on type and purpose of the signing. Sometimes a plate or plaque is affixed to a work zone sign or mounted below it to customize the sign.

Sign dimensions for contract projects are located in Standard Plan 616.10 and for maintenance projects are located in the MGS-04-01 Roll-up Signs.

EPG 903.1.4 contains additional information regarding the design of signs, including an Option allowing the development of special word message signs if a standard word message or symbol sign is not available to convey the necessary regulatory, warning, or guidance information.

Guidance. Non-standard work zone signs (i.e., legends or sizes not shown on Standard Plan 616.10) should be designed with the assistance of the Highway Safety and Traffic Division. Correspondence with the Highway Safety and Traffic Division on this design is to indicate these are work zone signs. The non-standard work zone signs should be detailed in the plans and listed under “Miscellaneous Signs” on the D-2BS sheet.

Standard. All signs used at night shall be retroreflective.

Option. Signs may be made of rigid or flexible material.

EPG 616.6.1.1 Flags

Option. Standard orange flags may be used in conjunction with signs during daytime hours. It is allowable to leave flags on signs when daytime work continues into nighttime.

Standard. When standard orange flags are used in conjunction with a sign, they shall not block the sign face.

EPG 616.6.1.2 Existing Sign Use

Option. Existing warning signs that are still applicable may remain in place within a TTC zone.

Guidance. All existing signs within the project limits should be shown on the TTC plan with a descriptive note indicating "UIP" (use in place), "cover" or "remove".

616.6.2 Sign Placement (MUTCD Section 6F.02)

EPG 616.6.2.1 Sign Location

Guidance. Signs should be located on the right-hand side of the roadway unless otherwise provided in the EPG.

To ensure maximum visibility, existing signs and other physical features (trees, sidewalks, billboards, commercial signs, etc.) should be considered when locating work zone signs.

Option. Where special emphasis is needed, signs may be placed on both the left-hand and right-hand sides of the roadway. Signs mounted on portable supports may be placed within the roadway itself. Signs may also be mounted on or above barricades.

EPG 616.6.2.2 Sign Mounting Height

Support. The provisions of this article regarding mounting height apply unless otherwise provided for a particular sign elsewhere in the EPG.

Standard. Rural Undivided Highways - 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 undivided highways in rural areas shall be 5 feet (see Standard Plan 616.10).

Urban Highways or Rural Divided Highways - 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 divided highways or highways in business, commercial, or residential areas where parking or pedestrian movements are likely to occur, or where the view of the sign might be obstructed, shall be 7 feet (see Standard Plan 616.10).

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

The bottom of a sign mounted on a barricade, or other portable support, shall be at least 1 foot above the traveled way.

Option. The height to the bottom of a secondary sign mounted below another sign may be 1 foot less than the height provided in the first three Standard paragraphs of EPG 616.6.2.2.

EPG 616.6.2.3 Sign Supports

Guidance. Neither portable nor permanent sign supports should be located on sidewalks, bicycle facilities, or areas designated for pedestrians or bicyclists.

Standard. Signs shall be mounted and placed in accordance with Section 307 of the U.S. Department of Justice 2010 ADA Standards for Accessible Design, September 15, 2010, 28 CFR 35 and 36, Americans with Disabilities Act of 1990.

Guidance. Except as provided in the following option paragraph, signs mounted on portable sign supports that do not meet the minimum mounting heights provided in EPG 903 should not be used for a duration of more than 3 days.

Option. The R9-8 through R9-11a series, R11 series, W1-6 through W1-8 series, M4-10, E5-1, or other similar type signs may be used on portable sign supports that do not meet the minimum mounting heights provided in EPG 903 for longer than 3 days.

Support. Methods of mounting signs other than on posts are illustrated in Figure 616.6.2.3.

Guidance. Signs mounted on Type 3 Barricades should not cover more than 50 percent of the top two rails or 33 percent of the total area of the three rails.

Standard. Signs and sign supports used together shall be crashworthy (see EPG 616.1.4). Where large signs having an area exceeding 50 square feet are installed on multiple breakaway posts, the clearance from the ground to the bottom of the sign shall be at least 7 feet.

Option. For mobile operations, a sign may be mounted on a work vehicle, a shadow vehicle, or a trailer stationed in advance of the TTC zone or moving along with it.

Support. Standard Plan 616.10 shows sign mounting requirements, post size and quantities requirements, and post installation details. The standard plans show detailed information for use of signs on posts, barrier, vehicles, and barricades.

Figure 616.6.2.3 Methods of Mounting Signs Other Than on Posts

Additional Guidance for Sign Supports For long-term duration projects, post or type 1 portable sign supports should be 5 ft. or 7 ft. depending on rural or urban applications. For short-term duration projects (up to 3 days), signs may be mounted on type 2 portable sign supports and should have a minimum height of 12 inches. Additional mounting heights for signs located on barrier and vehicles are located in Standard Plan 616.10. The sign mounting method is dependent upon the contractor’s operations and is not to be dictated on the plans. See Standard Plan 616.10 for mounting methods and post installation requirements. Sign relocation is only paid for post-mounted signs. MoDOT does not pay for temporary or portable sign relocations. If the designer judges post-mounted signs will be used on a project, a pay item for Relocated Signs (616-10.10) is to be included in the contract documents. Sign quantities are tabulated on the plans and are paid for by the square foot. The tabulation and any notes concerning the signs shall be consistent throughout the traffic control plan. Signs may be supported in one of four methods: on a portable support, post-mounted, vehicle-mounted or barrier-mounted. Portable signs are temporary traffic control signs affixed to a portable support such as an easel, fold- up sign stand, self-driving post, skid, barricade, etc. These signs are to be constructed of either a rigid or flexible substrate, as required, to meet crashworthiness requirements. A minimum mounting height of one ft., measured vertically from the bottom of the sign to the near edge of the pavement, is recommended. However, higher mounting heights should be considered on higher volume highways, on multi-lane highways, in urban settings, and where the sign is located in line with other traffic control devices to increase visibility of the sign. Mounting heights for regulatory and guide signs are as specified for post-mounted signs. Portable signs may be located adjacent to or within the roadway itself. However, a minimum lateral clearance of three ft., measured horizontally from the edge of the sign to edge of the designated traveled way, is recommended. Signs mounted in this manner may be left in place for up to three days. An exception to this duration is any crosswalk/sidewalk closure, any road closure, Horizontal Arrow, Double-Headed Horizontal Arrow, Chevron, DETOUR (within arrow) or Gore Exit sign. These sign may be left in place for over three days. When not in use, consideration should be given to removing portable signs from the temporary traffic control zone to discourage theft and limit potential hazards within the right of way. Picture 1: Easel portable sign. Pictures 2 & 3: Fold-up signs at 1-ft. and 5-ft. heights. Picture 4: Self-driving post. Picture5: Skid-mounted sign Post-mounted signs are temporary traffic control signs affixed to a breakaway support such as perforated square steel tube, u-channel, wood, etc.. These signs are constructed of a rigid substrate. A minimum mounting height of seven ft., measured vertically from the bottom of the sign to the near edge of the pavement, is recommended for urban highways and rural divided highways. A minimum mounting height of five ft., measured vertically from the bottom of the sign to the near edge of the pavement, is recommended for rural undivided highways. If a supplemental sign is mounted below another sign, the mounting height of the supplemental sign may be one ft. less than the heights specified. A minimum lateral clearance of two ft., measured horizontally from the edge of the sign to the edge of the roadway, is recommended for installations on roadways with curbed sections. A minimum lateral clearance of six ft., measured horizontally from the edge of the sign to the edge of the traveled way, is recommended for installations on roadways without curbed sections. U-Channel Post-Mounted Sign Vehicle-mounted signs, when allowed in this manual, are temporary traffic control signs affixed to a protective vehicle or pilot car at a recommended minimum height of four ft., measured vertically from the bottom of the sign to the pavement surface. For additional information, review Standard Drawing 616.10. Vehicle-Mounted Signs Barrier-mounted signs are temporary traffic control signs affixed to the top portion of a temporary or permanent traffic barrier. The method of attachment to the barrier must ensure a positive connection and minimize potential for vehicle snagging. Mounting heights for regulatory and guide signs are as specified for post-mounted signs. In order to accommodate narrow medians, see EPG 903.1.5. Barrier-Mounted Signs If the sign cannot be mounted by a method specified by EPG 903.1.14, Standard Plan 616.10, or Standard Plan 903.03, the mounting method is also to be specified in the plans.

616.6.3 Sign Maintenance (MUTCD Section 6F.03)

Guidance. Signs should be properly maintained for cleanliness, visibility, retroreflectivity, and correct positioning.

Signs that have lost significant legibility should be promptly replaced.

Support. EPG 616.24 provides examples of sign maintenance.

EPG 903.1.21 contains information regarding the retroreflectivity of signs, including the signs that are used in TTC zones.