Highlights This study aims to investigate the predictability of crash risk models. The predictability is defined as crash probability given the crash precursor identified by the crash risk model. We explore the relationship between crash frequency models and real-time crash risk models. An equation was derived to estimate approximately the predictability of crash risk models. We evaluate how critical issues, such as the threshold of crash precursor affects the predictability of crash risk models.
Abstract The primary objective of the present study was to investigate the predictability of crash risk models that were developed using high-resolution real-time traffic data. More specifically the present study sought answers to the following questions: (a) how to evaluate the predictability of a real-time crash risk model; and (b) how to improve the predictability of a real-time crash risk model. The predictability is defined as the crash probability given the crash precursor identified by the crash risk model. An equation was derived based on the Bayes’ theorem for estimating approximately the predictability of crash risk models. The estimated predictability was then used to quantitatively evaluate the effects of the threshold of crash precursors, the matched and unmatched case-control design, and the control-to-case ratio on the predictability of crash risk models. It was found that: (a) the predictability of a crash risk model can be measured as the product of prior crash probability and the ratio between sensitivity and false alarm rate; (b) there is a trade-off between the predictability and sensitivity of a real-time crash risk model; (c) for a given level of sensitivity, the predictability of the crash risk model that is developed using the unmatched case-controlled sample is always better than that of the model developed using the matched case-controlled sample; and (d) when the control-to-case ratio is beyond 4:1, the increase in control-to-case ratio does not lead to clear improvements in predictability.
Evaluation of the predictability of real-time crash risk models
Accident Analysis and Prevention ; 94 ; 207-215
2016-06-07
9 pages
Article (Journal)
Electronic Resource
English
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