Comparative Analysis of Freeway Exit Ramp Terminal Design Practices to Deter Wrong-Way Driving in Different States

Abstract

Although wrong-way driving (WWD) crashes are rare compared with other crashes, the severe outcomes resulting from these crashes make them an important traffic safety issue, especially on freeways. The initial point of origin for the majority of WWD crashes is the exit ramp terminal. During 2009–2013, the exit ramp terminals of full diamond and partial cloverleaf interchanges in Alabama experienced considerably higher frequency of wrong-way entries compared with those in Illinois. In this study, a comparative analysis is conducted between these two states to compare the differences in exit ramp terminal design practices and determine the differences that might have caused the relatively higher frequency of wrong-way entries at the exit ramp terminals in Alabama. The comparative analysis revealed that there is relatively higher usage of certain geometric design features and traffic control devices in Illinois, which contributed to deterring WWD. The lessons learned from this study can potentially benefit the 4E community (i.e., enforcement, education, emergency response, and engineering) in further understanding the best practices on off-ramp terminal design and traffic control devices features that have the potential to reduce WWD crashes on freeways.