Citation

Zhou Y, Himes S, Le T, Gooch J, Northup K, Pavao P. Transp. Res. Rec. 2022; 2676(7): 24-31.

Copyright

(Copyright © 2022, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.1177/03611981221076433

PMID

unavailable

Abstract

A road diet is a low-cost countermeasure which typically involves converting an existing four-lane undivided roadway to a three-lane roadway, reducing the section to two through lanes and a center two-way left-turn lane. The objective of this evaluation was to estimate the safety effectiveness of road diets by developing a crash modification factor (CMF) specific to the U.S. state of Rhode Island. To account for potential selection bias and regression-to-the-mean, an empirical Bayes before-after analysis was conducted, using reference groups of untreated four-lane undivided roadways with similar characteristics to the treated sites.

RESULTS indicated a 29% decrease (CMF = 0.71) in total crashes and a 37% reduction in fatal and injury crashes (CMF = 0.63). The expected results of the evaluation will help Rhode Island Department of Transportation to determine a statewide direction for implementation of the countermeasure.

Language: en

Keywords

crash analysis; crash modification factors (CMFs); crash prediction models; safety