aerial bridge 960x300

wildlife crossing structures mapIf you've driven the stretch of U.S. Highway 93 on the Flathead Indian Reservation, you've likely seen the "Animals' Trail", a 197-feet wide vegetated bridge that provides safe passage for wildlife to cross over the busy highway. 

That Animals' Trail may be the most visible, but it's just one of dozens of fish and wildlife crossing structures that line the 56-mile stretch of highway.

In total you'll find:

  • 41 fish and wildlife crossings (including the Animals' Trail)
  • 60 jump outs
  • 2 underpasses for livestock
  • 1 bicycle/pedestrian underpass
  • 18 miles of wildlife fencing
  • 8.7 miles of road length with wildlife fencing on both sides 

The Montana Department of Transportation, Confederated Salish and Kootenai Tribes, and Federal Highways Administration constructed these passages to improve safety by reducing wildlife-vehicle collisions and to protect wildlife migration corridors.

The structures are located in areas known for heavy wild life crossings and mortality, and/or locations where the surrounding landscape was best suited for the structures. Typically, you can find them near stream crossings and areas with protected habitat on both sides of the road.

fish and wildlife underpasses thumb

Fish and Wildlife Underpasses
The culverts and bridges are designed to provide safe crossing opportunities under the highway for wildlife. Structures that include a stream aim to resemble natural stream conditions for fish and other aquatic species.


wildlife passages aerial bridge thumbWildlife Overpass
Some large carnivores, deer, elk and moose tend to use vegetated highway overpasses more frequently than wildlife underpasses to access the other side of the road.


fencing thumbFencing
Eight-foot high wildlife fencing on both sides of the road keeps wildlife from entering the highway and directs them to crossing structures.


wildlife jumpout thumbJump Outs
Jump outs allow wildlife to safely jump down to the other side of the fence should they be caught in the fenced road corridor.



wildlife crossing guard thumbWildlife Crossing Guards
Modeled after cattle guards, wildlife guards discourage deer and other hoofed mammals from entering the fenced road corridor at access roads.

You can find dimensions of each of the wildlife crossing structures in this table. Part of the success of wildlife crossing structures comes from animals feeling secure in approaching or crossing the structures. We appreciate your interest, but please do not approach or enter the wildlife crossing structures; it is not allowed.

The following table details the types and dimensions of the underpasses on US 93 North.

TypeSize in FeetNumber
Cement culvert 10 x 14 1
Concrete box culvert 5 x 7 3
Concrete box culvert 6 x 4 5
Concrete footers/divided lanes 12 x 22 1
Conspan arches 9 x 28 2
Conspan arches northbound and southbound 14 x 43 1
Corrugated metal arch culvert 12 x 24 1
Corrugated metal arch culvert 12 x 22 2
Corrugated metal arch culvert 17 x 24 4
Corrugated metal arch culvert 24 x 13 2
Corrugated metal arch culvert 24 x 15.5 2
Corrugated metal arch culvert 6 x 4 1
Corrugated metal arch culvert 8 x 8 1
Corrugated metal pipe or concrete box culvert 7x5 1
Corrugated metal pipe or concrete box culvert 12 x 22 7
Multi span bridge (existing) - 1
Open span bridge 15 x 395 10
Open span bridge 10 x 100 1
Open span bridge 12 x 100 1
Open span bridge 16 x 131 1
Plastic coated corrugated metal culvert 6 x 4 2
Wildlife overpass 49 x 197 1

Student Art Contest


The People's Way Partnership conducted the Safe Passages for Wildlife poster contest to teach school-age children about the importance of wildlife crossing structures under and over highways for both human and wildlife safety.
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Please download this page (PDF) to send funds towards the People's Way Partnership outreach efforts!


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