Effectiveness of Changeable Message Signs in Controlling Vehicle Speeds in WorkZones: Phase 2

摘要

This report is the second phase of a longitudinal research study. The first phaseof the project, conducted by Garber and Patel, examined the short term effectiveness of CMS in reducing vehicle speeds in work zones. That research established that the CMS (with the radar unit) is more effective in reducing speeds in work zones than the standard Manual on Uniform Traffic Control Devices (MUTCD) signs. This study, while attempting to replicate the results obtained in phase I of the project, concentrated on evaluating the effect of duration of exposure of the CMS with radar on its effectiveness in reducing speeds and influencing speed profiles in work zones. The impact of length of the work zone and vehicle type on speed reductions was also studied.