A method for simplifying the analysis of traffic accidents injury severity on two-lane highways using Bayesian networks

Abstract

Introduction: This study describes a method for reducing the number of variables frequently considered in model- ing the severity of traffic accidents. The method's efficiency is assessed by constructing Bayesian networks (BN). Method: It is based on a two stage selection process. Several variable selection algorithms, commonly used in data mining, are applied in order to select subsets of variables. BNs are built using the selected subsets and their performance is compared with the original BN (with all the variables) using five indicators. The BNs that im- prove the indicators’ values are further analyzed for identifying the most significant variables (accident type, age, atmospheric factors, gender, lighting, number of injured, and occupant involved). A new BN is built using these variables, where the results of the indicators indicate, in most of the cases, a statistically significant improvement with respect to the original BN. Conclusions: It is possible to reduce the number of variables used to model traffic accidents injury severity through BNs without reducing the performance of the model. Impact on Industry: The study provides the safety analysts a methodology that could be used to minimize the number of variables used in order to determine efficiently the injury severity of traffic accidents without reducing the performance of the model.