Statistically modelling relationships between accident types and highway features

Although in recent years considerable progress has been made to establish r elationships between accidents and highway characteristics, no specific acc ident models are widely accepted by the highway engineering agencies. Four commonly used models are developed in this study, that is, two conventional linear regression models and two Poisson models. Accident data monitored b y the National Freeway Bureau in Taiwan are used to model statistically rel ationships between accident types and highway features. Traditional models are demonstrated to possess unsatisfactory statistical properties that cann ot adequately describe discrete, non-negative, random and sporadic accident events along a highway. Based upon statistic estimates, the Poisson models are shown to be more appropriate, accurate and reliable than the conventio nal linear regression models.