Safety problems in work zones are aggravated by the lack of uniform guidelines for determining speed limits for these situations. Inconsistencies in the methods used to determine work zone speed limits, noncompliance with the posted speed limit by motorists, and the growing practice of setting work zone speed limits through administrative decisions without benefit of an engineering study are major contributors to this safety problem. While the national Manual on Uniform Traffic Control Devices (MUTCD) presents guidelines for determining the speed limit on roads free of work activities, it fails to provide a procedure for setting work zone speed limits. In 1988, the AASHTO Highway Subcommittee on Traffic Engineering and the Construction and Maintenance Technical Committee of the National Committee on Uniform Traffic Control Devices unanimously concurred that research is urgently needed to establish a procedure for determining work zone speed limits.

The objective of this project was to develop a uniform procedure for determining work zone speed limits that could be used for construction and maintenance operations and accommodate, to the maximum extent possible, the often divergent interests of motorists, workers, and pedestrians. This project consisted of the following efforts: (1) An extensive literature review, interviews with knowledgeable individuals, and other appropriate survey techniques were used to identify current procedures and actual practices related to the determination of speed limits both generally and in work zones, and to assess motorist compliance with speed limits in work zones. (2) Data were collected and analyzed to identify work zone characteristics critical to setting speed limits and formulate procedures for determining work zone speed limits. The data collection sites included a sampling by geographic region, level of development (urban, suburban, rural), roadway classification, and type and duration of work zone activity. A procedure for determining work zone speed limits was developed and recommended for inclusion in Part VI of the MUTCD. An applications-oriented user's manual was prepared, which includes diverse examples describing the use of the recommended procedure.

Status: This research is complete, and NCHRP Research Results Digest 192, "Procedure for Determining Work Zone Speed Limits," provides a summary of the procedure for setting work zone speed limits. Other sections of the contractor's report will be included in the final report for the continuation project, NCHRP Project 3-41(2). The contractor's final report is available from the NCHRP.