Study On Traffic Safety Models For Highway Three-Leg Unsignalized Intersections

The rapid development of highway brings a lot of benefits for us. But unfortunately, people have to face the serious situation of challenge due to surging traffic crashes. From 2003-About 10,000 people killed in traffic crashes every year in China. How to reduce the fatality rate and protect people from traffic crashes is an important task for safety researchers and traffic engineers.Intersections are important net nodes in the road system. They play very important functions in the whole system. Their safety performance is associated with the roadway safety directly and affects roadway operating efficiency. Studies on intersection safety can help us to explore crashes mechanism, which is a vital theme in traffic safety field.Although intersection area only occupies a small fraction of the whole length of road, crashes proportion within intersection areas is pretty higher. Research on intersections'safety becomes more urgent. This dissertation is supported by the subsidiary programs on intersection safety of two important projects of the Ministry of Communications of China, which are"Highway safety audit of western area"of 2003 programs, and"Research on Highway safety application technology"of 2004 programs.Some intersections are prone to crashes because of two main reasons. The first one is that, drive behaviors are not in harmony with road design parameters. Traffic flow interweave mutually and bring out conflict points, merging points and diverging points in intersection area, which makes a great difference with that of basic segment of a highway. Drivers need complicated maneuvers and decision-making before entering intersection area. If a certain design parameter is not coordinated with driver behaviors, it will lead to maladjustment of dynamic system of human, vehicle, road and environment. Drivers'faults may destroy stability of the system combined with human, vehicle, and environment. Hence induce crashes during complicated operating process. The other reason is that some people don't comply with the traffic rules. It is an essential causation of crashes. A possible explaining for why people disobey traffic rule is that the design parameters or control style don't fit road user's prevailing demands. Just for these two main reasons and drivers'complicated judgments'processes, result in explore intersection crashes mechanism much more complicated. The dissertation will concentrate on this field.The subject of this dissertation is three-leg intersections with unsignalized control in highway system. There are two main objectives: One is to discuss crashes statistical characteristics and carry out a method to predict safety performance. The second one is that make further discussion on crashes inherent mechanism, especially on relationship between of driving behavior, waiting time and acceptance gap. Then the author will offer suggestions to some design methods to avoid dangerous drive behaviors.This dissertation based on the analysis of crashes and phenomenona of regulation-broken activities. With exploring driver'safety behaviors and crashes...