Assessing Safety of Signalized Intersections: Influence of Geometric Attributes and Regionality on Traffic Accident Risk

Abstract

Traffic accidents constitute a serious social problem. Thus, it is essential to identify and remove the risk factors affecting traffic accidents to enhance traffic safety at intersections. This study identified and quantified the main factors influencing traffic accident risk at signalized intersections to propose effective countermeasures. Google Earth was used to collect numerical data related to the geometric attributes of intersections in three regions in Japan: Kagawa, Shiga, and Aichi. A lognormal hurdle model that considered regionality and geometric attributes was then used to quantify factors influencing the risk of traffic accidents involving various types of collisions. The results indicate the existence of significant regional differences in the geometric attributes of intersections in those regions. The findings reveal that intersection size (indicated by the distance between stop lines), length of crosswalks, and setback distance of crosswalks generally and significantly influence all collision risk types; in addition, a compact intersection lowered the risk of all collision types. And in most cases, regional dummy variables were statistically significant. This finding suggests that in addition to intersection geometric attributes, regional differences in some factors influenced collision risk. Thus, it could be reasonably assumed that regionality stemmed from differences in driving characteristics.