Analysis on the Effect of Expressway Horizontal Curve Radius on the Driver's Visual Features

The driver's visual features is crucial for traffic safety. The horizontal curve radius has a significant effect on the driver's visual features when driving on the expressway curve sections, which include the eye gazing scope, eyeball moving speed and so on. Through the measured data of the eye tracker system, the relationships between the horizontal curve radius and operating speed,eye gazing scope or eyeball moving speed and other traffic and visual features were studied systematically. The influence law of horizontal curve radius on the driver's visual features and their calculation formula was obtained. These achievements were beneficial to determine the expressway horizental alignment that ensure driver's visual comfort and improve the comfort and safety of highway driving. Meanwhile it can provide us some supplementary and reference for the specification.