616.12 Work Zone Speed Limits

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MoDOT has the authority to set speed limits on the state highway system. This power extends to establishing speed limits in temporary traffic control zones, where the speed limit may be reduced from the normal speed limit for safety purposes. Work zones shall be designed to the normal posted speed limit.

A reduced speed limit should be carefully considered before it is imposed, as motorists will only reduce their speed if they perceive a need to do so. Any decision to reduce the speed limit based on an arbitrary, "across the board" or other inappropriate rationale may result in non-compliance with the reduced speed limit by motorists and a false sense of security for workers.

Should a reduced speed limit be deemed appropriate, the following table shows the recommended maximum speed reductions that may be imposed in temporary traffic control zones.

Table 616.12 Recommended Maximum Speed Reductions

Activity (i.e. Workers, Equipment or Material) Location Recommended Work Zone Speed Reduction (When Applicable)
10 ft. beyond edge of travelway to edge of right of way No speed reduction
In traffic lane or within 10 ft. of the traffic lane 10 mph
Head-to-head on multilane 10 mph
Special circumstances within a temporary traffic control work zone may warrant a lower speed limit than recommend above. All speed limit reductions greater than 10 mph shall be documented, submitted to and approved by the District Work Zone Coordinator.

After selecting a reduced speed limit based upon the table above, the following guidelines will assist in the proper installation and application of that reduced speed limit in the temporary traffic control zone.

  • On divided highways, the reduced speed is applicable to the affected direction of travel only.
  • Existing SPEED LIMIT signs within the temporary traffic control zone shall be covered or removed.
  • SPEED LIMIT signs indicating the normal speed limit should be installed at the end of the reduced area provided no other reduction is imposed within the next one-half mile or no existing SPEED LIMIT sign is located within the next one-half mile.
  • Reduced speed limit signing shall be removed, covered or turned from traffic when conditions requiring the reduced speed no longer exist.
  • For two-lane roadways, normal SPEED LIMIT signs are typically installed opposite the work zone SPEED LIMIT sign on the opposite approach facing traffic leaving the work zone.
  • Reduced SPEED LIMIT signs are not to be installed on side street approaches or ramps for work limited to main line only. Reduced SPEED LIMIT signs may be installed downstream from the ramp or side street to inform drivers of the work zone speed limit. If the work is on the ramp, or affects the ramp, reduced SPEED LIMIT signs are to be used.
  • Posted work zone speed limit shall not be below 35 mph, except when local ordinance provides for a lower speed. The lower speed shall be used when applicable.
  • Appropriate warning signs with advisory speed plaques should be used to advise of any specialized situations (i.e., temporary bypass, narrow lanes, etc.).
  • For approved speed reductions greater than 10 mph, additional notification should be provided through the use of the SPEED LIMIT XX AHEAD sign. Refer to EPG 616.12.3 Work Zone SPEED LIMIT Figures.
  • For approved speed reductions greater than 20 mph, the speed limit should be reduced in two stages. Refer to EPG 616.12.3 Work Zone SPEED LIMIT Figures.

616.12.1 WORK ZONE FINE Sign (CONST-3A)

Additional Info
About Signs Required for Assessing Fines
RSMo 304.582.1

The WORK ZONE FINE sign shall be specified on projects where all the following criteria are met:

  • Duration of the work zone is longer than 4 hours.
  • Reduced speed limits are in effect.
  • Normal posted speed limit is 60 mph or greater.
  • Workers will be present without positive protection (concrete barrier or guardrail).

If a lane closure is used on a roadway with two lanes in the direction of travel, two DO NOT PASS and two PASS WITH CARE signs and two CONST-3X, (SPEEDING/PASSING) plates shall be specified. WORK ZONE plaques shall be specified for all DO NOT PASS signs being used as part of the work zone signing sequence. If a lane closure is used on a roadway with three or more lanes in the direction of travel, the DO NOT PASS and PASS WITH CARE signs and SPEEDING/PASSING plates shall not be specified.

616.12.2 Sign Descriptions and Applications

Sign descriptions and applications are located in EPG 616.6 Temporary Traffic Control Zone Devices.

616.12.3 Work Zone SPEED LIMIT Figures

Fig. 616.12.3.1, Work Zone SPEED LIMIT Locations within Advance Warning Area
Fig. 616.12.3.2, Work Zone SPEED LIMIT Locations within Activity Area
Fig. 616.12.3.3, Work Zone FINE Sign and SPEED LIMIT Locations within Advance Warning Area
Fig. 616.12.3.4, Work Zone SPEED LIMIT Locations for Reductions Greater than 20 mph and Reduction in Two Locations
Fig. 616.12.3.5, Work Speed Limit Locations within a Lane Closure on Two-Lane Road Using Flaggers