Samenvatting
A forward obstacle/congestion warning system was installed at a black spot on the Metropolitan Expressway in Tokyo. After the warning service began, the number of accidents decreased considerably. However, other countermeasures were implemented around the same time as the warning service. Therefore, the effects of the warning service on traffic accidents should be analyzed separately. A change-point model is adopted to analyze the effectsand estimated using MCMC. The effect of repavement is proved to be most important and that of warning service using dedicated short range communication (DSRC) is secondary. These results are compared with those of the preceding analysis.