Bozeman Pass Wildlife Channelization ITS Project

Abstract

Animal-vehicle collisions (AVCs) are a growing concern as vehicle miles traveled and human encroachment into wildlife habitat continues to increase throughout the United States. Few studies have examined the application of intelligent transportation systems (ITS) to modify driver behavior to reduce these collisions. This study investigated the effectiveness of dynamic message signs (DMS), an ITS application, to disseminate seasonal animal movement advisories as a speed reduction tool on Interstate 90 in the Bozeman Pass area. Driver responses to wildlife advisory messages displayed via other sign applications were also evaluated in a driving simulator environment. In addition to evaluating driver responses to in an attempt to lower AVCs, wildlife-vehicle collisions and movements on Bozeman Pass were monitored on Bozeman Pass prior to the installation of 0.9 miles of wildlife exclusion fencing targeted on modifying wildlife movements; monitoring will continue after the installation to provide data to conduct a before-after analysis evaluating the effectiveness the wildlife exclusion fencing in terms of reducing AVCs and maintaining wildlife movements under the interstate via an existing bridge where the fence will be installed. The last component of this project documented impacts of AVCs on department of transportation maintenance operations. The speed study and driver survey on Bozeman Pass suggested that wildlife advisory messages posted on permanent and portable DMSs can reduce motorist speeds and drivers likely had heightened awareness due to the wildlife advisories, thus reducing the safe stopping sight distance of motorists, with the most significant reductions observed during “dark” conditions when the likelihood of AVCs is highest. Driving simulation study results showed that, compared to the traditional static wildlife warning signs, test subjects were more likely to see enhanced wildlife advisory signs and enhanced signs prompted subjects to drive at decreased speeds and they were more able to quickly respond to wildlife crossing the road. Pre-fencing road-kill monitoring spanning from 2001 to 2005 documented nearly more than 1300 AVCs on Bozeman Pass. Monitoring of wildlife movements in the Montana Rail Link (MRL) bridge area also occurred prior to the installation of the wildlife fencing. Fencing will be installed in 2006 and monitoring will continue to determine the effectiveness of the fencing. The outcomes from the fencing evaluation will be combined with results from this project to provide a single, comprehensive report documenting the measures applied to increase driver safety and decrease impacts on wildlife in the Bozeman Pass region. Impacts on maintenance operations were challenging to quantify; a more in-depth assessment of the costs of wildlife carcass removal and disposal versus the expenses related to applying and maintaining different mitigation measures would help determine the most cost-efficient techniques to reducing AVCs. In conclusion, the evaluation of measures to reduce AVCs via driver and animal behavior modifications, and the preliminary assessment of the impacts of these issues on maintenance operations will help guide future decisions related to managing wildlife-transportation conflicts in the northern Rocky Mountain region.