Analyzing Drivers' Responses to Portable Changeable Message Signs in Rural Highway Work Zones

Abstract

The number of work zones has been increasing in the highway system of the United States because of rising needs in highway construction and maintenance. Highway work zones disrupt normal traffic flow and create safety problems. To improve safety by reducing the risk of vehicle crashes, temporary traffic control devices have been developed and implemented in work zones. A Portable Changeable Message Sign (PCMS), one of the temporary traffic control devices, is capable of displaying a variety of messages to inform motorists of unusual driving conditions in highway work zones. To better utilize a PCMS in work zones, there is a need to investigate the effectiveness of a PCMS and determine the optimal deployment location of a PCMS in the work zones. The primary goals of this research project were to determine the effectiveness of a PCMS on reducing vehicle speeds and the optimal deployment location of a PCMS in the upstream of one-lane two-way rural highway work zones using the field experiments and survey methods. A slower vehicular speed allows for greater reaction time to avoid crashes, and potentially creates a safer environment for drivers and workers in the work zones. Vehicles were divided into two categories, namely passenger cars and trucks. To accomplish the goals of the research project, the following main tasks were performed: 1) determining the effectiveness of a PCMS on reducing passenger cars and trucks speeds under three conditions (PCMS On, Off, and Absent) using field experiments, 2) developing vehicle speed profile models, 3) using the speed profile models and measured mean speeds to determine the optimal deployment range of a PCMS in the upstream of work zones, 4) investigating drivers' reactions after seeing a PCMS using the survey method, and 5) comparing the speed reductions of passenger cars and trucks to determine if a PCMS could be utilized to reduce the risks of truck-related crashes in one-lane two-way rural highway work zones. Utilizing the findings of this research project, traffic engineers will be able to determine if, where, and how a PCMS needs to be deployed in one-lane two-way rural highway work zones to mitigate vehicle crash risks. As a result, the safety of work zones will be improved and resources will be better utilized.