Implementing a 70kph speed limit on a former 90kph regional road: A simulator study on the role of sign configuration and distraction

Abstract

This study hinges upon the notion of speed limit credibility on roads where the imposed speed limit (70kph) is perceived as too low in function of the traffic environment. More specifically, the effect of sign configuration and distraction will be investigated to determine how these affect the driver's speed control in the specified traffic environment. In total, 47 volunteers participated in driving simulator experiment. Each participant completed two trips, i.e., with and without secondary task) consisting of three 6km sign configuration segments (i.e., speed limit repetition after every intersection within the 70kph section. In the other two configurations, a speed decrease was followed by a speed increase close to the end of the 70kph section. The moment of speed decrease was however different between the two configurations. Importantly, in all three configurations, after some time of driving through an environment that invites drivers to exceed the limit, speed increased close to the end of the section, however, only in the no repetition configuration, speed became higher relative to the start of the section and to the other configurations. Distraction resulted in a lower driving speed across the three sign configurations. These findings and their practical implications are further discussd in the paper.