Estimating countermeasure effects for reducing collisions at highway-railway grade crossings.
Frequently transportation engineers are required to make difficult safety investment decisions in the face of uncertainty concerning the cost-effectiveness of different countermeasures. For certain types of highway-railway grade crossings, this problem is further aggravated due to the lack of observed before and after collision data that reflects the impact of specific countermeasures. This study proposes a Bayesian data fusion method as an attempt to overcome these challenges. In this framework, we make use of previous research findings on the effectiveness of a given countermeasure, which could vary by jurisdictions and operating conditions to obtain a priori inference on its expected effects. We then use locally calibrated models, which are valid for a specific jurisdiction, to develop the current best estimates regarding the countermeasure effects. By using a Bayesian framework, these two sources are integrated to obtain the posterior distribution of the countermeasure effectiveness. As a result, the outputs provide information not only of the expected collision response to a specific countermeasure but also its variance and corresponding probability distribution for a range of likely values. Examples from Canadian highway-railway grade crossing data are used to illustrate the proposed methodology and the specific effects of prior knowledge and data likelihood on the combined estimates of countermeasure effects.
Saccomanno
Frank F
FF
Department of Civil Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ont., Canada N2L 3G1. saccoman@uwaterloo.ca
Park
Peter Young-Jin
PY
Fu
Liping
L
D000056:Accident Prevention / Q000706:statistics & numerical data; D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D001499:Bayes Theorem; D002170:Canada; D006801:Humans; D011890:Railroads