DATA-DRIVEN METHODS FOR REDUCING WRONG-WAY CRASHES ON FREEWAYS

Driving the wrong way on freeways has been a nagging traffic safety problem since the interstate highway system was founded in the 1950s. Despite four decades of highway striping and sign improvements at freeway interchanges, the problem persists. This paper is to determine the contributing factors to wrong-way driving on freeways and to develop promising, cost-conscious countermeasures to reduce this driving errors and related crashes. Wrong-way crash data from Illinois Department of Transportation (IDOT) crash database were collected with 632 possible wrong-way crashes. The real wrong-way crashes were further identified by reviewing the wrong-way crash reports hardcopies and information from other resources. Characteristics of wrong-way driving behaviors were analyzed and statistical analyses were conducted to identify the contributing factors of wrong-way crashes on freeway. The state-of-the-art roadway safety management process recommended by the Highway Safety Manual (HSM) was adopted to diagnose the wrong-way driving behavior on Illinois freeway and develop the specific wrong-way crashes management procedures. The first three steps, network screening, diagnosis and countermeasure selection was developed in details. The whole procedure developed could be used to guide the management of freeway wrong-way crashes in the future. The specific procedure of transportation network review, candidate location identification and site ranking for freeway wrong-way crashes was established firstly. Based on the collected wrong-way crash data, the safety performance function (SPF) for wrong-way crashes on freeway was developed with the annual average daily traffic (AADT) and segment length being the independent variables. The procedures for candidate wrong-way crash sites diagnoses with crash data, historic site data, field condition and other information were described step by step. The methods for contributing factors identification were proposed and the Haddon matrix for wrong-way crashes on freeway was constructed finally. Methods for selecting wrong-way crash countermeasures from the perspective of four E\u27s based on crash analysis finding, site-specific contributing factors and geographical characteristics were discussed, and research needs on wrong-way crash management in the future were recommended finally