Principal Investigator: Steven Schrock
Crashes that occur at bridge sites tend to be more severe than those on typical segments of roadway. The greater density of objects in the roadside environment, including railing designed for zero deflection on impact, means the vehicles which leave the roadway at bridge sites may have more limited opportunities for recovery. The rigidly defined roadway width on bridges limits options for routing traffic around closed lanes and, even where sufficient width exist to route a given volume of traffic around a closed lane readily, driver perception of being corralled through may reduce average speed resulting in more potential for delay through the site. This project will seek to quantify the impact of truck related crashes at bridge sites in terms of hours, lane closures and volume of traffic impacted. The investigation will build on previous research on bridge crashes in Kansas to develop Crash Modification Factors for bridge site characteristics relevant to truck crashes. Crash Modification Factors give highway agencies the opportunity, using the methodology provided in the AASHTO Highway Safety Manual, to compare options for reducing expected crash frequencies for highway facilities. By combining the expected reduction in crash rate with the estimated impact on traffic for truck related accidents at bridge sites, owners have the ability to maximize the operational benefit of limited funds for construction and maintenance of highway facilities. Improved operation also maximizes the economic benefit of such facilities.