An Evaluation of the Effectiveness of Wildlife Crossings on Mule Deer and Other Wildlife
AdvisorTian, Zong Z.
Civil and Environmental Engineering
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ABSTRACTHighways retrofitted with overpasses and underpasses for wildlife use have been implemented in the United States and the world. The observed level of mortalities of mule deer and other wildlife species on U.S. highways appears to have negative consequences on wildlife population. Studies in other states indicate that more than 50% of the deer-vehicle collisions nationwide are not reported and there are no records for deer-vehicle collisions that occurred in remote areas although records for collisions within or near urban areas may be reported. The primary objective of this study is to evaluate the effectiveness of wildlife overpasses, using a case in the State of Nevada. The 4.1-mile study section is along the U.S. 93 Highway in Elko, NV, with 3 miles of fencing on both sides of the highway. This thesis focuses on evaluating the level of effectiveness of the overpass in reducing deer-vehicle collisions. An Empirical Bayes approach was applied to compare the `before' and `after' crash changes. A benefit-cost analysis of the wildlife overpass is also included to identify its effectiveness considering factors like number of mortalities, deer-vehicle collisions threats to human injuries or fatalities, and the construction costs. Key Words: Wildlife Overpass and underpass, Deer-Vehicle Collisions, Before-After Study, Benefit-Cost Analysis, Empirical Bayes Estimate.