Lower Speed Limits Don't Protect Mule Deer, Study Finds

Jan 17, 2020

Credit By USFWS Mountain-Prairie (Mule Deer on Winter Range in SW Wyoming) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0) or Public domain], via Wikimedia Commons

Reducing speed limits might sound like a cheap, easy way to keep both human and wildlife safe on Wyoming roads.

Not so, says a new study from the Wyoming Department of Transportation and the Nature Conservancy in Wyoming.

Corinna Riginos led the study, which reduced nighttime speed limits on a few highways in southwestern Wyoming. She said there was no drop in vehicle-animal collisions, because despite the signs, drivers barely reduced their speed.

Riginos says it's a bit like texting while driving, which most people know is dangerous.

"And yet people do it all the time," she said. "So, if we're having trouble with that, I think it's a bigger ask to think that public awareness and more signs is going to get people to slow down 15 mph when they're driving on a highway."

The study recommends building crossing structures, such as overpasses or underpasses. Crucially, these strategies do not rely on changing human behavior, and are more successful at reducing collisions.

"Crossing structures are the only really proven way to solve the problem," Riginos said. "And we do need to continue to support efforts to build those crossing structures and not assume that we're magically going to find a cheaper alternative."

In November, Wyoming received a $14.5 million grant from the U.S. Department of Transportation to build wildlife crossings between Big Piney and La Barge.

Have a question about this story? Contact the reporter, Jeff Vctor, at jvictor@uwyo.edu.