A Development of Traffic Accident Estimation Model by Random Parameter Negative Binomial Model: Focus on Multilane Rural Highway

Safety Effects of Freeway Hard Shoulder Running

“…On the other hand, further analysis of the results reveals no relationship between lane width and changes in the frequency of total crashes (r = 0.159, p = 0.478), between lane width and changes in the frequency of serious crashes (r = −0.114, p = 0.612), between shoulder width and changes in the frequency of total crashes (r = 0.175, p = 0.436), and between shoulder width and changes in the frequency of serious crashes (r = 0.004, p = 0.987). These results are in contrast with those obtained in previous studies [32,33] that found a relationship between width values and crash occurrences. The results of this study may be due to small changes in the lane and shoulder widths for the sites included in this study.…”

“…Based on the results of his earlier study, one researcher recommended a two-foot minimum shoulder width for a concrete median barrier [32]. In one of the few studies conducted in South Korea, it was found that the design criteria for satisfying the minimum 1.25 m shoulder width had a significant impact on crash occurrences [33]. Since hard shoulder running is built with a shoulder width of less than 0.5 m in South Korea, drivers may have difficulty keeping proper lane positioning and thus, presumably, experience more crashes.…”