Interchange ramp terminals are important parts of the highway system. However, crashes that occur at ramp terminals are not well researched. Additionally, very few research efforts have developed safety performance functions for interchange ramp terminals. This research collected data from six none-frontage-road diamond interchanges in Madison, Wisconsin, and developed a safety performance function for signalized diamond interchange ramp terminals by using a generalized linear regression approach. The factors considered include the following: volume, clearance interval (i.e., yellow and all-red intervals), off ramp exclusive right turn phase, and spacing between two adjacent terminals. The major findings suggest three outcomes: (1) the crash frequency will increase with the deficient yellow or all-red intervals; (2) the probability of rear-end crashes increases and the probability of angle crashes decreases if the interchange ramp terminals have an off ramp exclusive right turn phase; and (3) as terminal spacing increases, the crash frequency will increase, with crash type dependent on terminal spacing.
Development of a Safety Performance Function for Signalized Diamond Interchange Ramp Terminals
Tenth International Conference of Chinese Transportation Professionals (ICCTP) ; 2010 ; Beijing, China
ICCTP 2010 ; 1034-1046
2010-07-22
Conference paper
Electronic Resource
English
Development of a Safety Performance Function for Signalized Diamond Interchange Ramp Terminals
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