URBAN ROAD TRAFFIC VISUAL ENVIRONMENT RELIABILITY EVALUATION BASED ON AMOUNT OF INFORMATION PERCEIVED BY DRIVERS' CENTRAL VISION

摘要

A well-designed urban traffic system should be safe and efficient, which can providedrivers with rhythmic driving experience. Under this circumstance, drivers could achieve abalance between relaxation and tension. For one thing, drivers can keep alert and drivevehicles unhurriedly in case of generating distraction due to excessive relaxation. Foranother, they have enough time to discover and handle any potential events in case thattoo much nervousness will result in fatigue. Hence it can decrease the probability of theoccurrence of drivers' distraction and fatigue behaviour. Rhythmic driving means that thereis a sense of rhythm during the driving process, which is mainly reflected from operatingspeed. Although many factors may affect the driving speed, studies have shown thatdrivers' control of speed is closely related to the information they perceive, especially thevisual information that needs to be processed. If the information is complicated andnumerous, it will lead to emotional stress, heavy workload and fatigue, so sometimesdrivers have to slow down to increase the time for processing information. On the otherhand, if the information is fairly simple to process, drivers are likely to spare little time on it.On this condition, drivers may produce distraction behaviour and raise their speedunconsciously. Therefore, as a kind of active safety technology，the urban traffic systemshould provide precise information with a proper amount to ensure traffic relatively highsecurity, so that drivers are neither prone to distraction nor easy to generate fatigue. In thispaper, after calculating drivers' central visual amount of information under urban trafficenvironment, we understand the close correlation between rhythmic driving and visualamount of information drivers have to handle. Research finds out that if the gradient ofvisual amount of information is too large, drivers will be liable to feel fatigue and stressed,but if this gradient is too small, drivers will be distracted easily. Based on these results, amethod is proposed that uses gradient of visual amount of information to analyze thereliability of urban road traffic visual environment.