Problem Statement Major construction upgrades are underway along a 28km section of State Route 260 in central Arizona that exhibits a high incidence of collisions (e.g., >4km/year) between wildlife, primarily Rocky Mountain elk (Cervus elaphus), and vehicles. As this highway is being upgraded from a narrow two-lane roadway to a fourlane divided highway, 12 sets of large underpasses (in addition to 5 sets of bridges) are being constructed to facilitate wildlife passage across the highway corridor and minimize the incidence of wildlife-vehicle collisions. Construction is being accomplished in stages (5 total), with the fi rst 8-km section with two underpasses completed in 2001 and the second 12-km section with fi ve underpasses nearing completion. Limited elk-proof fencing has been erected in association with the completed underpasses and those under construction, and alternatives to fencing (e.g., large boulder rip-rap and steep cut slopes) are also being applied. Our research focuses on evaluating the effectiveness of the underpasses, fencing, and other measures in reducing the incidence of wildlife-vehicle collisions and maintaining wildlife permeability. Our fi ndings are being applied though adaptive management to make modifi cations to underpass design and fencing to increase use by wildlife. Project Objectives The primary objectives of our research project, ongoing since 2002, are to: 1) Determine the effectiveness of the full complement of measures to minimize the incidence of wildlife-vehicle collisions along State Route 260. 2) Evaluate the degree to which wildlife permeability across the highway is maintained. 3) Provide ongoing construction implementation guidance to Arizona Department of Transportation (ADOT) project managers throughout all construction phases.