MDOT – MDOT Will Not Issue New Work Zone Speed Limit Guidelines

In response to construction worker safety concerns raised by MITA and the Michigan Laborers’ District Council, MDOT will not issue the proposed Bureau of Highways Instructional Memorandum 2005-B, Guidelines to Establish Speed Limits in Work Zones. The “draft” Instructional Memorandum was approved by MDOT’s Engineering Operations Committee on March 3, 2005, with a planned 2005 construction season implementation.

The proposed guidelines incorporated the recommendations of the 1996 NCHRP Research Results Digest, No. 192, Procedures for Determining Work Zone Speed Limits, which have been endorsed by the American Association of State Highway and Transportation Organizations (AASHTO) and implemented by several state DOT’s. The NCHRP national research effort which incorporated data from seven states, 68 work zones, 27 speed studies, and 66 accident data collection sites, found correlations between work zone speed variance and accident rate incidences. The research concluded that smaller reductions in work zone speed limits may result in minimal accident rate increases. The net affect of implanting the NCHRP recommendations could mean high speed limits in some work zones, especially on freeway routes.

MITA’s worker safety concerns focused on the fact that the research and the speed and accident analysis associated with it did not, or could not, consider the worker safety element and the potential impacts to workers safety that would go along with higher speed limits and increased accident rates in work zones.

MDOT, in partnership with MITA, plans to initiate a series of listening and education sessions about work zone traffic operations over the next several months.

If you have any questions on this matter contact Glenn Bukoski, at 517-347-8336 or by e-mail at