Research On Cognitive Behavior-based Speed Humps For Expressways

China’s vehicle population increases continuously with the rapid development of its economy. Its traffic mileage of expressways has leaped to the first place in the world; the subsequent catastrophic traffic accidents are, however, stimulating our nerves. It is found in the study that speeding is a major cause of traffic accidents and an important determinant of the severity of expressway accidents. And effective measures to control the speed at accident prone sections could fundamentally reduce accidents resulted from speeding, ensuring safe travel and improving the level of road safety.For this purpose, compulsory measures including speed limit signs are mainly applied for expressways now, but they are unsatisfactory since the limited speed value is far lower than the allowed driving speed and the driver may venture to overspeed under the effect of negativism, which threatens the traffic safety. The optical illusion-based speed hump is able to attract the attention and change the perception of driver about the traffic environment from the perspective of cognitive psychology and, in the meantime, guide the driver with moderate stimulus intensity to slow down naturally to reasonable speed. In addition to factors taken into account such as the driving comfort and deceleration smoothness, the set-up of speed hump present a less monotonous expressway environment and play a role in easing and relieving the boredom, dullness and visual fatigue. There is, however, a lack of specific regulations and effective scientific standards on expressway speed hump among the traffic codes of China, thus leading to the confusion in application of speed humps to current highways and making some of speed humps less unreasonable and effective.This paper presents three types of speed humps, i.e., the three-color and three-dimensional, the fishbone shaped and the quadrangle shaped, based on the cognitive behavior of driver and the principle of optical illusion. They are set up by the following procedures:to draw the plan of expressway to be tested and the parameter diagram of these speed humps by using CAD software; to product ive files of these three speed humps with Multigen Creator; to import ive files into the database of road modeling software used for driving simulator; to create expressway model with the modeling software; export from the database and pave. the speed humps at appropriate positions. Then by utilizing our driving simulator and the simulating technique,47tested drivers are invited to carry out the simulation test and subjective assessment, and the test verification on the calming effect of these three speed humps and to specify the advantages and disadvantages, as well as applicable sections via comprehensive analysis. The research results could provide certain theological basis and reference for the road administration.