Driver´s characteristic of speed perception on freeway at night

In order to establish reasonable speed limit standard on freeway at night, it is necessary to study driver´s characteristic of speed perception under different driving circumstance at night. Data of driver´s perception speed at daytime and nighttime were analyzed comparatively. The impacts of actual driving speed, horizontal curve radius and longitudinal slope on driver´s perception speed were analyzed quantitatively. It is discovered that the accuracy of driver´s perception speed at night decreases compared with daytime, and there is no relation between driver´s perception speed and longitudinal slope. Relationship models were established between driver´s perception speed at night and actual driving speed, horizontal curve radius. It indicates that there is positive linear, negative logarithm relation between driver´s perception speed and actual driving speed, horizontal curve radius at night.