Highlights Analyzed the safety of two roadway median types by considering the truck impacts. Developed crash modification factors for the conversion of roadway median types. In addition, Crash Modification Factors (CMFs) for conversion from TWLTL to RM were derived based on both predicted and expected average crash frequencies according to the HSM. This result will be useful for analyzing roadway safety performance.
Abstract Introduction: Due to their size and weight, trucks require more space and time to make left turns when exiting or entering a roadway. Therefore, appropriate median treatments are critical for roadways with substantial truck traffic. The two-way left-turn lane (TWLTL) and raised median (RM) are the two types of median most commonly used to improve roadway mobility and manage roadway accessibility. However, previous studies on these median treatments have focused primarily on the general traffic conditions and geometric roadway features without considering the truck traffic impact. Method: To fill this gap, this study investigates the truck impacts on TWLTL and RM by considering two major influencing factors – truck percentage and roadway access point density. First, a negative binomial regression is developed to analyze the relationship between crash frequency and various influencing factors. Next, the crash rate difference analysis between the TWLTL and RM is conducted to identify critical points for these two factors. Results: The findings indicate that, compared with RM, TWLTL has significantly higher crash frequency, especially for roadways with a higher percentage of trucks. This suggests that the percentage of trucks should be taken into consideration when selecting an appropriate type of roadway median.
Two-way left turn lane or raised median? A truck safety based study
Journal of Safety Research ; 74 ; 109-117
2020-04-16
9 pages
Article (Journal)
Electronic Resource
English
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