SH-21 Wildlife Overpass at Cervidae Peak, MP 19.3

What’s the Problem?

State Highway (SH) 21 experiences high numbers of collisions between vehicles and wildlife. Idaho Department of Fish and Game and Idaho Transportation Department collected carcass data and found 77 deer and elk carcasses hit by vehicles on SH-21 between milepost 10 and milepost 22. SH-21 corridor lies within a critical habitat linkage area for deer, elk, antelope and other wildlife and stands between the historic home range of these animals, from summer range to winter range and vice versa primarily within B/SNF, BRWMA and adjacent public lands.

Purpose of the Project

Reduce vehicle and wildlife collisions on SH-21.

Project Description

Construction of a wildlife over-crossing at milepost 19.3 and big game exclusion fence paralleling SH-21. The exclusion fence will include access and maintenance gates as needed. The fence will tie into existing fence improvements. Wildlife jump-outs will also be installed to allow animals trapped between fence lines adequate escape routes from the highway corridor. Cameras will be installed on and around the over-crossing to capture and observe animal usage.

Project Partners

  • Idaho Transportation Department
  • Idaho Department of Fish and Game
  • Forest Service
  • City of Boise
  • Federal Highway Administration – Western Federal Lands Highway Division

Anticipated Timeline

  • Design – Fall 2019 – Summer 2022
  • Contract Advertisement & Award – Winter 2022
  • Construction – 2023

Project Photos

Proposed location of wildlife over-crossing

Proposed location of wildlife over-crossing.

Game trails along SH-21

Game trails along SH-21.

Existing big game exclusion fence

Existing big game exclusion fence.

Example wildlife jump out

Example wildlife jump out.

View a larger interactive map of the project area.

Project Details
Project # ID DOT 21(1)
Project Name SH-21 Wildlife Overpass at Cervidae Peak, MP 19.3
Location Near Boise
Status In Development

Contact Information

Project Manager: Lindsay Higa
Email: lindsay.higa@dot.gov

Federal Highway Administration
Western Federal Lands Highway Division
610 East Fifth Street
Vancouver, WA 98661
360-619-7700