Microsimulation and the Evaluation of Safety Levels in the Presence of Roadside Obstacles

Abstract

Traffic microsimulation has been used for the analysis of road safety. In particular, some studies have confirmed that the reproduction by simulation of user behaviour under different traffic flows and geometry conditions can identify near crashes events that are a good base to estimate real crash risk. According to recent researches it appears that microsimulation tools can evaluate road safety performance and allow engineers to take appropriate countermeasures at specific points of the road network. The results of these approaches have been promising, though, all ongoing research has overlooked one important issue in the estimation of traffic safety levels: single vehicle crashes. According to statistics, collisions with fixed objects result in above 40% of all vehicle fatal crashes. Common used safety indicators are limited in their application since, in fact, they are based on conflicts techniques that do not consider roadside obstacles and barriers. The objective of this paper is to present a specific application of microsimulation software which is able to consider also potential conflicts with roadside objects. A specific microsimulation model add-on has been developed for the estimation of new road safety indicators that considers also potential crashes with roadside objects. First results are very promising and the developed software was applied on Tritone microsimulation package and can be used as an add-on also for other common used microsimulation packages such as Vissim and Aimsun.