Study On Speed Control And Visual Search Of Driving Behavior At Urban Signal Intersection

Because of the characteristics of mixed traffic mainly, which makes the intersection be the bottleneck of the road traffic, and the section which accidents happen frequently. For going through the intersection safely, the driver must be able to filter critical information and control speed reasonably, which can help to avoid traffic conflict effectively. Therefore, studying on speed control and visual search of driving behavior at the intersection, which have important significance to guide drivers going through the intersection safely, to avoid traffic conflicts effectively, to reduce accidents, and to improve traffic capacity of the entire road network.This paper will lie on the urban signal intersection, analyze driving behavior at the intersection through real vehicle tests in real traffic environment, by using GPS to record the speed that drivers approach to the intersection and go through the intersection, with the help of EyeLink II to record visual search of drivers'. Before analyzing the data from the tests, we divide a complete process of intersection driving into two parts by the stop line, which consist of the driving before the stop line (intersection) and the driving through the intersection. Intersections would be differentiated into three kinds, which are going straight (named F), turning left (named LT) and turning right (named RT). Then each one is also divided into three kinds by different states of the driving before the intersection, which consist of keeping moving straight (named P) and keeping moving until arriving at the intersection (named S) and starting to moving before the intersection (named W). According to the different circumstances, this article analyzes driving behavior before the intersection and through the intersection.Results indicate that, the driving behavior before the intersection, in the circumstance of P, drivers slow down properly before arriving at the intersection. In the circumstance of W, with respect to turning right and going straight,drivers will turn left at the intersection, before the intersection slow down slightly. In the circumstance of F-S, drivers don't slow down until they are apart from the intersection in 100m, and with a deceleration of 0.74m/s2. In the circumstance of RT-S, drivers don't slow down obviously until they are apart from the intersection in 60m, and with a deceleration of 0.54 m/s2.However, the driving behavior through the intersection, in the circumstance of F-S, drivers start from the stop line, go through the intersection with an acceleration of 0.53 m/s2. In the circumstance of RT-S, drivers drive into the intersection with an acceleration of 0.73 m/s2, after a steady driving, pull out of the intersection with an acceleration of 0.57 m/s2. In the circumstance of RT-W, drivers drive into the intersection with a deceleration of 0.43 m/s2, pull out of the intersection with an acceleration of 0.54 m/s2.On the basis of divide of visual fields, in the course of driving at the whole intersection, no matter what circumstances before the intersection or through the intersection, the drivers pay the most attention to forward area, and visual search begins from forward area, then passes through a certain area, finally comes back to forward area. Going straight, the drivers perform visual search in both sides to compensate for information, but rarely paid the attention to the rear area of car. Turning left, the drivers pay more attention to the area of left side when going before the intersection, and mainly perform the mode of visual search with C-L-C (visual search from the area of center to the area of left then back to the area of center), the drivers pay more attention to the area of right side when going through the intersection, and mainly perform the mode of visual search with C-R-C (visual search from the area of center to the area of right then back to the area of center). Turning right, the drivers pay more attention to the area of right side when going before the intersection, and mainly perform the mode of visual search with C-R-C, while passing through the intersection, the drivers pay more attention to the area of right side too, but mainly perform the mode of visual search with C-L-C.The driving behavior before the intersection, in the circumstances of P and S, most drivers overspeed, and visual search is not so wide, or fail to give attention to signal lights. The driving behavior through the intersection, visual search of drivers'is not so wide, which is the main problem.The research was sponsored by National Science Foundation (50908019).