Field Evaluation of Motorist Reactions to Reduced Work Zone Speed Limits and Other Work Zone Conditions

Abstract

Many factors are taken into consideration in procedures to determine whether a reduced regulatory speed limit in a work zone is warranted. Low levels of compliance with work zone speed limits continue to show, however, that there is a disconnect between procedures to establish regulatory speed limits and motorists’ actual choice of speed in work zones. An improved understanding of how the conditions used to justify reduced speed limits in work zones actually affect speeds could improve the speed limit selection process. To address this need, researchers conducted field studies in Texas work zones to determine motorists’ speed choices adjacent to conditions that were used to warrant reduced speed limits. On the basis of the findings, researchers concluded the following: when no work zone conditions were apparent, speeds downstream of reduced work zone speed limit signs decreased only slightly, independent of the speed limit reduction. Motorists reduced their speeds in work zones when they perceived a need to do so. How much speed was reduced, however, appeared to depend on the normal operating speed of the roadway, the imposing nature of the situation, and enforcement activities. Some work zone conditions used to justify reduced speed limits were not adequately perceived by motorists. Thus it was these conditions that were most in need of enforcement, because motorists were less likely to reduce their speeds voluntarily. Reduced work zone speed limits that were left in place when conditions did not warrant them led to high levels of noncompliance.