title: Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: an exploratory analysis.
abstract: The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car-truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies.
authors.affiliation: Center for Transportation Research, The University of Tennessee, 600 Henley Street, Knoxville, TN 37996, USA. Electronic address: CDONG5@UTK.EDU.
authors.forename: Chunjiao
authors.initials: C
authors.lastname: Dong
authors.forename: David B
authors.initials: DB
authors.lastname: Clarke
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Richards
authors.forename: Baoshan
authors.initials: B
authors.lastname: Huang
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D001334:Automobile Driving / Q000706:statistics & numerical data*; D001336:Automobiles / Q000706:statistics & numerical data*; D001499:Bayes Theorem; D002958:City Planning; D004779:Environment Design / Q000706:statistics & numerical data*; D006801:Humans; D015233:Models, Statistical; D018986:Motor Vehicles / Q000706:statistics & numerical data*; D015999:Multivariate Analysis; D016012:Poisson Distribution; D012044:Regression Analysis; D013714:Tennessee
keywords: Bayesian method; Crash frequency; Geometric design; MVPLN model