This research aims to investigate the cause of the accident that occurred on public passenger van by in-depth accident investigation method. The Method is a powerful and reliable standards and generally accepted. Researchers conducted a thorough review and collect information about bus accident resulting in the death and injury. The results of the analysis showed that characteristics of majority of the accidents occur only one public passenger van(Single-Vehicle Accident). Factors related to the cause of the accident was is mistakes and shortcomings and the interaction between people and road. However considering the overall error of the defect (the driver) is the most of the accident. The analysis of the cause and severity of the accident was found the Deaths by the number of many loss due to the Burned and Physical shocks . Result in death. And Door of the public passenger van was damaged out of the car to make it slow. And most of the passengers could not escape in time.

This research aims to evaluate the effectiveness and limitations of the Road Safety Audit in Thailand. The evaluations would be used as a guideline to set Road Safety Audit policy for transport authorities in order to enhance the traffic safety in the construction area. In the study the construction project route 318 Trat-Had Lek part2 (Section1) Sta.1+900.00 to 20+000.00 (total distance of 18.100 kilometer) was selected as a case study. The accident statistics occurred before the construction and during the construction were compared to analyze the effectiveness of the Road Safety Audit used in the project. The result of the study shows that the main cause of the accident are traffic management traffic sign and marking as well as pavement surface. Therefore the researchers have provided some recommendations against the accident causes. Finally the operations of the contractors according to the recommendations were monthly summarized to measure the effectiveness of the recommendations.