| With the rapid development of our national society and economy, the construction of expressway has also made remarkable achievements. The rapid development of expressway has greatly improved the overall technological level of the highway network and optimized the transportation structure, which has played an important role in alleviating bottlenecks of transportation and has promoted the further economic development and social progress. However, the expressway has been plaguing our managers and users by its high accident rates and casualty rates. In particular, the implementation of develop-the-west strategy, the mileage of expressway in mountain areas is increasing, and the proportion of expressway in mountain areas is growing. Owing to the limitation of geographic and geomorphic conditions in heavy mountainous areas, highway geometric design of expressway in mountain areas will inevitably use some limit design indicators, resulting in traffic accidents occurred frequently in some sections, which become accident-prone locations.Since the 1990s, some researchers began to study the accident-prone location, and put forward some methods of identifying the accident-prone location based on extensive foreign existing research, which were useful exploration for the investigation and remediation of accident-prone location. However, present studies are short of systematic and in-depth theoretical research for the accident-prone location. Not only there is no standard definition of the accident-prone location, but also there is no detailed analysis of formation mechanism and prevention research for the accident-prone location. Therefore, it is necessary to select the typical accident-prone location, and analyze the relationship of the characteristics of traffic accidents and some influencing factors, such as highway spatial structure, traffic operation environment, and analyze the formation mechanism of traffic accidents, and put forward some prevention measures of traffic accidents, and predict prevention effects of prevention measures, which become an important and hot problem in the field of traffic safety.In addition, with the issue of the national expressway network planning in 2004 and the subsequent issue of the expressway network planning of each provinces (autonomous regions and municipalities), the construction of expressway in China are in order, and the development and construction pattern has moved from contented demand type to professional layout type. By the end of 2009, there is 6.5 million kilometers expressway in China, and expressway network in the eastern region has been formed, and the basic expressway network in the central region has already appeared, and the skeleton expressway network in the western region has been formed. With the gradual improvement of expressway network in China, the central work of expressway management department is transferring from the construction to the operation and management, and the efficient transportation and safe operation of expressway will be the main work in the future.Therefore, the profound study of the laws of expressway traffic accidents, in particular, the typical accident-prone location, can not only reveal the mechanism of expressway traffic accidents and contribute to determine potential safety hazard, but also formulate some targeted improvement measures in order to reduce the number of traffic accident and mitigate accident severity, and lay the theoretical basis for traffic accident prevention.In this context, the main content of this dissertation is summarized as follows:(1) The mechanism of cause of traffic accident for expressway was described, which is the imbalance product of the dynamic system composed of people, vehicles, roads and environment. Then, research findings of some scholars at home and abroad were summarized from four aspects:human factors, vehicle factors, road conditions and environmental factors.(2) In order to analyse the relationship between the number of traffic accidents and potential influencing factors, nine independent variables were selected, and two kinds of different section divided method were adopted, which produced 1 km fixed-length segment and the longitudinal grade consistent segment. Three general form of traffic accident frequency temporal-spatial model were constructed, which are traffic accident frequency hourly distribution model, traffic accident frequency weekly distribution model and traffic accident frequency monthly distribution model. Four statistical model, which were Poisson regression model, Negative Binomial regression model, Zero-inflated Poisson regression model and Zero-inflated Negative Binomial regression model, were used to fit six constructed models. Then traffic accident frequency temporal-spatial analysis model was determined in terms of goodness of fit test.(3) Accident severity is the dependent variable, which is a categorical variable with three categories, including fatal accident, injured accident and only property damage accident. Of thirteen candidate independent variables obtained from three aspects:time, road spatial structure and traffic operation environment. The combined stepwise method was used to analyse the significant correlation between dependent variable and independent variables. The results show that seven independent variables are significant associated with dependent variable. Then traffic accident severity spatial-temporal analysis model for expressway based on cumulative Logistic model was built. Finally, the developed model was tested from goodness of fit and predictive accuracy.(4) On the basis of prevention measures in 2005, three candidate prevention schemes were put forward. The traffic accident frequency temporal-spatial analysis models and traffic accident severity temporal-spatial analysis model developed in Chapter 4 were used to re-estimate the accident frequency and severity under the condition of four prevention schemes. Finally, prevention effects of four prevention schemes were analysed both with and without traffic safety measures.(5) According to the loss cost of traffic accident and traffic safety facilities, the comprehensive benefit of traffic safety prevention schemes was analysed. On the basis of four prevention schemes described in Chapter 5, the cost-effectiveness ratio was used to evaluate the economic effects of four candidate prevention schemes. A Sensitivity analysis was used to search the significant influencing factors which can influence the cost-effectiveness ratio.
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