Optimization Design and Experiment on Plane Layout of Edge Line Marking for Speed Reduction

It is known that the installation of edge line marking can help reduce driving speed.Theoretically, higher edge rate density leads to higher perception speed, so as the effect of speed reduction. However, too high edge rate density may result in progressively reduction of overestimating speed even underestimation, due to critical flicker frequency. To further strengthen the application effect of edge line marking, plane layout of double-row and triple-row of edge line marking were proposed from the essence of critical flicker frequency and mechanism of speed reduction of edge line marking. In simulation experiment, different speed perception under different plane layout was measured. The results showed that double-row edge line marking could overcome the restriction of critical flicker frequency and get higher perceived speed. While participants tended to perceive three adjacent edge line markings as a whole when triple-row edge line marking was adopted, which embodied the law of proximity in Gestalt psychology, and then the overestimation of perceived speed had no significant difference with the one when single-row edge line marking was used. Based on these, road experiments were carried out on the Hangrui highway in China with optimization of single-row and double-row edge line marking. The result showed that the latter performed better with speed reduction. The average speed, 85% speed and standard deviation of speed respectively dropped 9.26km/h, 10.48km/h and 3.0km/h, with separately reducing range of 9.0%, 9.0% and 38.0%, which got better improvement than that using single-row edge line marking.