Sensitivity of crash models to alternative specifications

Noland, RB; Karlaftis, MG

dc.contributor.author	Noland, RB	en
dc.contributor.author	Karlaftis, MG	en
dc.date.accessioned	2014-03-01T01:23:04Z
dc.date.available	2014-03-01T01:23:04Z
dc.date.issued	2005	en
dc.identifier.issn	1366-5545	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16793
dc.subject	Count data	en
dc.subject	Crash models	en
dc.subject	Drunk driving	en
dc.subject	Negative binomial models	en
dc.subject	Policy analysis	en
dc.subject	Safety-belts	en
dc.subject.classification	Engineering, Civil	en
dc.subject.classification	Operations Research & Management Science	en
dc.subject.classification	Transportation	en
dc.subject.classification	Transportation Science & Technology	en
dc.subject.other	transportation policy	en
dc.subject.other	transportation safety	en
dc.title	Sensitivity of crash models to alternative specifications	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.tre.2005.03.002	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.tre.2005.03.002	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	This paper examines the sensitivity of policy conclusions that are derived from crash models using various specifications. Our analyses compare models specified as crash rate or population normalized models (i.e., fatalities per capita or per vehicle miles traveled) adjusted to account for serial correlation in the error term with negative binomial count models with the total number of fatalities as the dependent variable. Our analyses focus on the interpretation of key policy variables, especially the association between safety-belt laws and administrative license revocation laws on fatalities. Evaluation of statistical significance of parameters, elasticities derived from the models and total fatalities associated with changes in key variables are examined. Results suggest that negative binomial models tend to be more robust and display less variation in results than those linear regression models that account for serial correlation. From a policy perspective, we found no evidence that passage of administrative license revocation laws that automatically suspend the license of a drunk driver have been effective while laws requiring safety-belt usage have been effective. Our results suggest that providing confidence intervals on elasticity estimates and estimated fatalities would provide policy makers with greater confidence in the results of model estimates. (c) 2005 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Transportation Research Part E: Logistics and Transportation Review	en
dc.identifier.doi	10.1016/j.tre.2005.03.002	en
dc.identifier.isi	ISI:000230164700006	en
dc.identifier.volume	41	en
dc.identifier.issue	5 SPEC. ISS.	en
dc.identifier.spage	439	en
dc.identifier.epage	458	en