From traffic conflict simulation to traffic crash simulation: Introducing traffic safety indicators based on the explicit simulation of potential driver errors

This paper presents a methodology that could support researchers and engineers in the important and original issue of the simulation of crashes and the evaluation of consequences on existing microsimulation packages. The proposed approach, by introducing potential driver errors, specifically allows consideration of the potential conflicts with road side barriers and obstacles and between vehicles that are moving on trajectories (close in space) that do not intersect. The severity of resulting crashes can, then, be evaluated in terms of accurate crash dynamic variables. Moreover, the methodology presented in the paper allows researchers to develop new conflict indicators that overcome many limitations of traditional traffic safety conflict indicators which, unfortunately, do not consider: the types of vehicle that are involved in a conflict, roadside obstacles or barriers, vehicles which are travelling on non-conflicting trajectories and the severity of a potential resulting crash. The paper applies a specific family of new simple and reproducible conflict indicators and provides the information necessary to develop new algorithms and simulation methodologies which, introducing human error in traffic simulation, may revolutionize the way traffic microsimulation can be used to establish a traffic safety for different scenarios. Feasibility tests on simple networks are presented and the results show the feasibility of making safety evaluations for different traffic scenarios by introducing driver errors.