Statistics Analysis of Relations between highway geometric alignment features and Road Safety

Considering the facts that it is very difficult to collect enough traffic accident data and traffic accidents can not be simulated on real highways, the comparison analysis on different segments with different geometric alignment features on same highways was carried out by applying the statistic method of Before-After Study. The regularity of road safety performance and the effects of highway alignment features were studied by using Before-After Study with limited data in this paper. The method of statistics analysis especially about two kinds of alignment features was established. Then, the relation between highway alignment features and road safety performance was investigated.