Dynamic Maximum Speed Limits

Abstract

Application of dynamic maximum speed limits may lead to positive effects for the environment, safety, and traffic flows. However, the efficacy of this dynamic traffic management measure depends largely on the behavior of drivers (i.e., compliance). In this paper, it is conjectured that compliance does not depend solely on attitudes of drivers but also depends on drivers’ perceptions of the dynamic maximum speed limit signs and mental workload. It is assumed that characteristics of the dynamic maximum speed limit signs influence the perceptions of drivers as well as their mental workload. It is, however, not yet clear to what extent characteristics of the signs influence perception, mental workload, and compliance of drivers. Therefore, two driving simulator experiments were performed to investigate the influence of four factors on drivers’ perception, mental workload, and compliance. The factors studied were the signs’ content, implementation, location, and frequency. From the results, it followed that different effects of these factors could be observed. For example, it was observed that the frequency with which dynamic maximum speed limit signs were provided to the drivers had a significant influence on perception and compliance, although a significant effect on mental workload could not be established. The paper concludes with a discussion of results and recommendations for future research.