Revisit Traffic Volume and Traffic Conflict: A Safety Evaluation on 3-Arm and 4-Arm Intersections in Hong Kong

The relationship between traffic volume and traffic safety has been one of the key issues in traffic safety research. This paper tries to re-examine this relationship by looking at 3-arm and 4-arm intersections in Hong Kong. For each intersection, the sum, product, and variance of traffic volumes from each arm are calculated. Three sets of variables are extracted considering all arms, major two arms, and two arms with the most and the least traffic volume. A linear model and a negative-binomial model are built to model the relationship between crash count and indicators. The results show that the negative binomial is better than the linear or the classic Poisson model. The best indicators for both 3-arm and 4-arm intersections are the sum and variance of traffic volume in all arms. Our results could be insightful to select traffic volume-related indicators when building crash count models at intersections in the future.