SR 20 - North Cascades Highway Wildlife Safety Study

SR 20 - North Cascades Highway Wildlife Safety Study map thumbnailStudy news

Washington State Department of Transportation (WSDOT) is currently working with faculty at Washington State University's, School of the Environment on a study collecting information about the patterns of deer crossings and factors contributing to deer-vehicle collisions along SR 20 in Okanogan County's Methow Valley. It focuses on the area between Twisp and Early Winters Campground and we have been collecting data related to both mule deer and white tail deer populations. Research to collect field data began in early 2017 using game cameras placed along the highway, visual tracking and documentation of deer sightings and carcass counts, as well as new field surveys to develop more accurate land cover maps.  The study was expanded in 2018 to include spatially tracking deer movements using radio collars.

Why is WSDOT conducting this study?

The number of wildlife-vehicle collisions has been rising in the United States as traffic and speeds increase on highways that intersect wildlife habitat. This has led to concern for human safety, financial burdens, and impacts on wildlife populations. SR 20 lies within the Methow Valley in Okanogan County, where Washington’s largest wintering concentrations of migratory mule deer exist. The goal of the SR 20 Wildlife Safety study is to better understand which environmental factors are affecting deer-vehicle collisions here and to provide management recommendations specific to the community’s needs and the characteristics of this road, which could reduce the number of deer-vehicle collisions each year.

SR 20 wildlife study - Deer in culvert

The Next Steps

Data collected for this study and is now being analyzed by WSU. Results of the study and management recommendations will be provided in a final report to Western Federal Lands (WFL) and shared publicly on this webpage, expected in July.

The most recent phase of the project (Feb. - Mar.) included a public event - the Mule Deer summit in Omak (on Feb.23) and an on-line survey asking for your feedback, sharing your perception of the factors driving deer-vehicle collisions, as well as which of the possible solutions are suited to the Methow.

The outreach was successful in that the Mule Deer summit drew more than three dozen participants and 362 people took the on-line survey!


July 2019 - Report findings and management recommendations.


Funding for this study was provided by a $106,775 Federal Lands Access Program (FLAP) grant from the Western Federal Lands division of the Federal Highway Administration (FHWA), matched with $28,225 of State funds.


Piper Petit, North Central Region Transportation Engineer
Phone 509-667-2876