A MICROSCOPIC TRAFFIC SIMULATION MODEL FOR SAFETY ASSESSMENT AT SIGNALIZED INTERSECTIONS

摘要

The usage of traffic simulation to evaluate the safety of signalized intersections is an innovative approachto assess performances of various layouts or operations upon the safety of these facilities. This studypresents the development of a microscopic simulation model aiming at the safety assessment ofsignalized intersections. This paper starts with a comprehensive discussion regarding the basicrequirements for such a simulation tool. The proposed simulation model integrates many key behavioralmodels of road users such as stop/go decision at the onset of yellow, turning paths, turning speeds, start-up response time and pedestrian gap acceptance models and so on. The main feature of these empiricalmodels is that they consider the stochastic behavior of road users. Furthermore, they are sensitive to thelayout and the operation of signalized intersections. This paper discusses how different conflicts arepresented inside the simulation by demonstrating the mechanism of one of these conflicts. Modelvalidation and a case study are conducted. The validation results show that the simulation modelreasonably represents the conflict occurrence at signalized intersections, which proofs that such a tool canbe a reliable approach for the safety assessment. A case study is conducted to compare the performanceof compact layout intersections with wide size ones. Trends of safety improvements are observed in thesimulation results, although a generalized conclusion could not be made.