Xuesong Wang,Hangfei Lin,Xiaohong Chen
Abstrac:While it is generally agreed that operational conditions have an effect on traffic safety, their relationship has not been well defined at a level of detail that adequately supports operation and planning performance measurements. Signalized intersections are the most complex locations on the roadway network, and they are vital to the efficiency and safety of transportation systems. Based on the data collected at 164 four-legged signalized intersections in the State of Florida, this study investigated the relationship between level of service (LOS) and safety at signalized
intersections. The LOS was calculated for three time periods: a.m. peak, midday, and p.m. peak. The crash count data models were applied to fit crash frequency models for total crashes in order to investigate LOS and safety relationship. Overall, the LOS indicator is a significant factor for predicting crash occurrence at intersections. However, the models show that the operational condition itself (by only including the LOS indicator) is not sufficient to predict the safety status. LOS “D” is a desirable level which is associated with less total crashes.