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原文传递 Analysis of Crash Characteristics on Freeways with Depressed Medians in Southcentral Alaska

题名：	Analysis of Crash Characteristics on Freeways with Depressed Medians in Southcentral Alaska
作者：	Bham, G. H.; Hafele, B.; Jones, K.
关键词：	Median safety##Crash severity##Crash analysis##Driver behavior##Median crashes##Crossover crashes##Rollover crashes##Logistic regression##Kernel density##Hotspots##Lighted roadways##Glenn highway##
摘要：	The characteristics of crashes on depressed medians of four freeways in South-central Alaska were examined under winter conditions. Cross-median crashes (CMC) were dispersed randomly along the freeways analyzed. CMC were 2.5 times more likely to cause a severe injury crash compared to an in-median crash. Rollovers were 72.9%, a very high percentage, among all median crashes. Median slops of 6H:1V (flatter) and 4:1/5:1 (steeper) were found to have similar frequency of cross-median and rollover crashes. With a median width of 32 ft (excluding inner shoulders), 54.7% of median crashes occurred. With a width of 36 ft, median crashes per mile were the highest for different crash types. As median width increased, in general, median crash frequency decreased. Two regression models were developed: (a) Median rollover crashes were associated with severe injury crashes, driver inexperience, horizontal curves, median width between 26 and 40 ft, surface ice, and specific periods of the day, and (b) CMC were associated with multiple vehicles, light trucks, after sunset on lighted roadways, and pavement rutting. Spatial analysis conducted identified nine top hot+spots: five segments on New Seward Highway, three on Glenn Highway including location of median crashes, and one on Minnesota Drive. Six interchanges were identified for detailed examination.
总页数：	85
报告类型：	科技报告