Motorcycle impacts into longitudinal traffic barriers such as w-beam guardrails frequently result in severe or fatalrider injury. Although special traffic barriers and barrier retrofit devices are available to mitigate the injuryconsequences of these crashes, research suggests that these countermeasures are cost-effective only at locationssusceptible to this crash type. Unfortunately, little information is available on specific roadway characteristics ofthese crashes, such as horizontal curve radius, to help designers identify high risk locations. The objective of thisstudy was to (1) determine specific roadway and roadway alignment characteristics associated with motorcycle tobarrier crashes and (2) investigate the influence of these characteristics on resulting rider injury. Data includedpolice reported motorcycle crashes coupled with detailed roadway data from two states, Washington and Ohio. Atotal of 1,511 motorcycle impacts to traffic barriers were analyzed and used to develop binary logistic regressionmodels to predict rider injury severity. Motorcycle impacts with barriers were found to be overrepresented onhorizontal curves, ramp sections, and on sections with grade in excess of 3 percent. Based on the availablecurvature data, the sole recommendation for placing motorcycle-to-barrier crash countermeasures on curves withradius less than 820 feet may not be prudent in US states as less than 40 percent of these crashes occur on thesecurves. Rider characteristics, such as helmet usage and alcohol involvement, were found to have a larger influenceon injury severity in comparison to associated roadway characteristics. The developed models suggest thathorizontal curves, vertical grades less than 3 percent, posted speed limits greater than 45 mph, and traffic volumesless than 10,000 vehicles per day increase rider injury risk, although these results were not statistically significant.
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