title: On factors related to car accidents on German Autobahn connectors.
abstract: We make an attempt to identify factors that explain accidents on German Autobahn connectors. To find these factors we perform an empirical study making use of count data models with fixed and random coefficients. The findings are based on a set of 197 ramps, which we classify into three distinct types of ramps. For these ramps, accident data is available for a period of 3 years (January 2003 until December 2005). The negative binomial model with some random coefficients proved to be an appropriate model in our cross-sectional setting for detecting factors that are related to accidents. The most significant variable is a measure of the average daily traffic. For geometric variables, not only continuous effects were found to be significant, but also threshold effects indicating the exceedance of certain values.
authors.affiliation: FedEx Express Europe, Middle East, Indian Subcontinent and Africa, Cologne, Germany. mgarnowski@fedex.com
authors.forename: Martin
authors.initials: M
authors.lastname: Garnowski
authors.forename: Hans
authors.initials: H
authors.lastname: Manner
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D016010:Binomial Distribution; D003430:Cross-Sectional Studies; D004779:Environment Design; D005858:Germany; D015233:Models, Statistical; D016012:Poisson Distribution; D012044:Regression Analysis; D014186:Transportation / Q000706:statistics & numerical data*