According to statistical crash data at intersection in Thailand (Figure 3), 9-13% of all crashes and 10-15% of all fatal crashes on national highways occurred at intersection. Based on the data from 2008-2011, crashes at intersection caused more than 1,300 deaths per year, and the trend is increasing continuously. For the crashes at unsignalized intersection, it has been found that poor sight distance is one of the major contributing factors to the crashes, while the red light running behavior has been reported as the major contributing factor of the crashes at signalized intersection. The red light running behavior is caused by not only the human error, but also the poor design of traffic signal timing and traffic light installation.
In this project, the roundabout will be implemented as the engineering measure for the safety improvement at intersection. The roundabout has been proven as a safety countermeasure due to the reduction in vehicle speeds, the reduction in conflict points, and the improved crash rate and injury rate records. In addition, the roundabout can lower overall delay than other controlled intersections in typical conditions.