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Citation |
Zhao J, Kargel A, McDaniel-Wilson C, Kolody K, Zhou H. J. Transp. Eng. A: Systems 2023; 149(5): e04023021. |
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Copyright |
(Copyright © 2023, American Society of Civil Engineers) |
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DOI |
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PMID |
unavailable |
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Abstract |
A safety treatment of shoulder rumble strips, shoulder widening [from 0 to 0.6 m (2 ft)] and pavement resurfacing (RSR) was deployed to over 644 centerline km (400 mi) of rural two-lane highways in Missouri. The effectiveness of the RSR treatment was evaluated with the empirical Bayesian before/after study method based on the roadway characteristics, traffic and crash data collected. Crash modification factors (CMF) for 20 categories of crash severity and/or collision type were calculated. Generally, the RSR treatment is effective for improving the safety performance of rural two-lane roads, especially for fatal and injury crashes. The RSR treatment is specifically effective for run-off road and head-on crashes. A cumulative residual (CURE) analysis reveals that fixed-value CMFs for all annual average daily traffics (AADT) range are likely to result in biased estimation on the RSR's safety effectiveness. The crash modification function (CMFunction) was introduced in this study and a sample size of 32 was selected to develop the CMFunction based on the sensitivity analysis results. CMFunctions were developed for two collision types of different crash severities. The CURE plot indicates that crashes predicted with CMFunctions are more accurate than those with CMFs and therefore CMFunctions are more reliable than fixed-value CMFs for evaluating the effectiveness of safety treatments. Language: en |
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Keywords |
Crash modification factor (CMF); Crash modification function; Pavement resurfacing (RSR); Rumble strips; Safety treatment; Shoulder widening |