Research on the Relationship between Dynamic Message Sign Control Strategies and Driving Safety in Freeway Work Zones

Several studies have researched the effect of dynamic message signs (DMSs) on the driving safety in work zones. However, only a few studies have examined the design of DIM control strategies in work zones. The purpose of this study is to investigate the effects of DMS control strategies on driving decisions and behaviors and to improve the driving safety in work zones by changing the content and placement of DMSs. In this study, five control strategies are proposed by combining five DMSs with different contents ("change lane" versus "go straight"). A total of 32 participants participated in this study. Each participant drove in five scenarios in a high-fidelity driving simulator corresponding to strategies 1-5. The results show that the control strategies have a significant effect on drivers' decisions and behavior (e.g., the driving speed, acceleration, and lateral placement). All strategies reduce the drivers' speeds and improve their control stability and compliance. After conducting analytic hierarchy process (AHP) analysis, strategy 2 was removed because the approaching speed exceeded the speed limit. The weight vectors of strategies 1, 3, 4, and 5 under free-flow traffic and traffic jam conditions are Upsilon(free-flow traffic )= [0.25,0.28, 0.17, 0.23] and Upsilon(traffic jam) = [0.17,0.28,0.2,0.3], respectively. These results show that strategy 4 is not suitable for free-flow traffic in work zones, while strategies 5 and 3 are suitable for traffic jams in work zones. Strategy 3 is suitable for both free-flow traffic and traffic jams. 'I he first occurrence of a decision sign that contains lane change content is key to the driver's decision; in addition, the position of signage with such information should gradually be moved closer to work zones with increasing traffic flow.