Project overview: Animal-vehicle collisions are a growing safety, socio-economic, and ecological concern as vehicle miles traveled and human encroachment into wildlife habitat increases throughout the United States. More than 1 million deer-vehicle collisions occur annually in the United States resulting in more than 200 fatalities, 29,000 injuries, and costing $1.1 billion in vehicle damage alone. Vehicle-related wildlife mortality can threaten some wildlife populations' long-term viability, which, in turn, can impact the ecological integrity of ecosystems. Transportation and natural resource agencies are searching for potential solutions to this ubiquitous "side effect" of transportation systems.

Numerous measures to reduce animal-vehicle collisions have been tried with varying degrees of success. The effectiveness of most of these measures is limited or uncertain. The most promising method is wildlife fencing (with wildlife passages to reduce habitat fragmentation), which has been shown to reduce reduce animal-vehicle collisions by 80-90%.

CERI began a study to assess the amount and nature of roadkill on Interstate 90 over Bozeman Pass in 2000. Data on roadkill locations and species has been systematically collected since 2001. Between 2001 and 2005 at least 1,336 animals were killed; over half were deer, but at least 34 elk, 48 coyotes, 18 black bears, 18 red fox, and 8 mountain lions, have also been killed.

Using these roadkill data CERI convinced the Montana Department of Transportation to include a section of wildlife fencing in their plans to rebuild a bridge over the Montana Rail Link crossing near Bear Canyon. In 2004 CERI constructed a track bed to record the number of animals crossing underneath the bridge. Two years of data were collected from this trackbed. Remote cameras were placed in culverts to record animal movements. The bridge was replaced in 2006 and lengthened to provide more room for wildlife to cross under the highway. Fencing was then installed to direct animals underneath the Interstate through the bridge or through a pair of large culverts. The fencing was completed in the spring of 2007 and CERI began a monitoring project to determine the effectiveness of the fencing at reducing roadkill and increasing animal movement underneath the highway.

The three-year monitoring plan includes seven field data collection tasks and a management, analyses and reporting tasks. These tasks include the following:
1. Road kill surveys between Bozeman and the Jackson Creek interchange;
2. Track bed monitoring of wildlife movements under the MRL bridge;
3. Remote camera monitoring of wildlife movements at fence ends;
4. Infrared counter monitoring of wildlife movements at jump outs;
5. Track bed monitoring of wildlife movements at fence ends and jump outs;
6. Remote camera monitoring of wildlife movements in two culverts at east end of fence;
7. Opportunistic snow tracking in MRL bridge and fenced area; and
8. Project management, data management, analyses, and reporting.

The wildlife fencing was part of a Montana Department of Transportation Interstate bridge replacement project over the MRL tracks east of Bozeman. The wildlife fencing is an attempt to reduce animal-vehicle collisions and re-direct wildlife to travel underneath the highway through a railroad underpass and some existing culverts.

As part of this experimental project, the Craighead Environmental Research Institute (CERI), in partnership with the Western Transportation Institute (WTI) and the Montana Department of Transportation (MDT), has been studying wildlife movements and roadkill along Bozeman Pass since 2000. The area near milepost 314 has been the site of higher than average roadkills, especially for black bears, moose, and deer.

Three years of data on animal movements through the old railroad bridge were collected prior to construction by observing tracks on a bed of sand and dirt that was regularly raked clean. American Wildlands (AWL) and other volunteers helped construct the track bed. Motion sensor camera were placed in culverts under I-90. Since the bridge replacement and wildlife fencing installation in 2006, CERI began the process of monitoring movements across a new track bed and set up new motion sensor cameras in the culverts. Although it is too soon to know if there is a significant reduction in animal-vehicle collisions through this stretch of highway, the outlook is promising.

In the first 7 months of the project no mammals have been killed on the highway within the fenced area. One concern with fences like this is that animals may wander onto the Interstate at the end of the fence and get stuck on the road. As they try to get out they may cross the highway several times and thus be more likely to get killed. For this reason MDT included four jump-outs in the fencing design to enable animals to "jump out" of the highway right-of-way. At eight feet high, these jump-outs are too high for animals to jump into the right-of-way. Only one animal, a coyote, has been recorded jumping out. One black bear climbed up the jump-out and got inside the fence but found his way out somewhere down the road. Several deer have been recorded near the fence ends, but they walked back out without getting trapped inside. And, there appear to be more deer than before crossing through the railroad underpass and more bears than before passing through the culverts.

MDT also funded projects by WTI and AWL to study the effects of warning signs and reduced speed on motorist's awareness and roadkill rates. Reduced speed does seem to reduce the number of animal-vehicle collisions, but it appears that the most effective way to reduce animal hits is to keep the animals off the highway altogether. After two more years we'll have a better idea how effective this fence is, and we can hopefully use similar techniques to reduce roadkill in other areas of the Pass and throughout Montana.

Our Final Report for 2006 with the Western Transportation Institute can be downloaded here. ( Bozeman Pass Wildlife Channelization ITS Project FINAL REPORT. [1.6MB] )

A recent article from the Bozeman Chronicle can be downloaded here. ( I-90 project helps prevent wildlife fatalities [4.8MB] )( smaller version of article alone [186KB] )

For More Inforamtion...
Bozeman Pass Wildlife Linkage and Safety Study
Additional Detail 2002
Additional Detail 2004
Additional Detail 2006