Evaluation of Methods to Reduce Speed in Work Zones

This study involved an evaluation of the effectiveness of the California Highway Patrol (CHP) combination Radar Detection/Changeable Message Sign (CHP-CMS) trailers to manage traffic speeds in highway work zones. The CHP-CMS trailer is a radar-equipped CMS trailer unit outfitted with revolving or flashing lights similar to those used on CHP vehicles. The main objective of this study was to test the following hypothesis: does the CHP-CMS trailer unit provide an effective deterrent to speeding, thereby slowing traffic in the work zones. The results of this study validated this hypothesis with the understanding that the validation was based on a total of three field tests due to the limited scope and time duration of this study as well as availability of actual work zones for testing. A repeatable test methodology based on the use of speed sensors distributed through the work zone was developed.