The effect of different delineator post configurations on driver speed in night-time traffic: A driving simulator study

•We conduct a simulator study on how different delineator post configurations affect driver speed.•Absence of delineator posts leads to reduced speed.•If delineator posts are placed continuously along the road, the exact configuration does not affect speed much.•A potential strategy to reduce driver speed in curves with a small radius is to use even more compact spacing between delineator posts in these curves than in curves with a large radius.

The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii. Fourteen drivers participated in the study and the results show that absence of delineator posts leads to reduced speed. However, provided that there are delineator posts continuously present along the road, the overall driver speed is basically the same, regardless of the spacing between the delineator posts. The results also imply that to reduce driver speed in curves with small radius, using more compact spacing of posts in these curves as compared to in curves with a larger radius, could be a potential strategy. Additionally, the speed reducing effect of a secondary task was only prevailing where the task was initiated.