CDOT installs animal-detection signs

System alerts drivers along stretch of road between Durango, Bayfield

by Shane Benjamin
Herald Staff Writer

Article Last Updated; Tuesday, September 30, 2008

In an effort to reduce animal-vehicle collisions, the Colorado Department of Transportation has installed a wildlife-detection system along a one-mile stretch of U.S. Highway 160 between Durango and Bayfield.

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Cyndi Stevens, construction project manager for the wildlife-detection system, triggers the warning system along a one-mile stretch of U.S. Highway 160 east of Durango on Monday. The $1.2 million test project is aimed at reducing animal-vehicle collisions.

Kevin Curry, left, and Mike Somsen, both with the Colorado Department of Transportation, check the computer control unit of the wildlife-detection system along U.S. Highway 160 east of Durango on Monday. Curry is the engineering project manager and Somsen is the highway-maintenance supervisor.

The system will detect the presence of large animals near the road and activate 40-inch by 60-inch lighted signs that read "Wildlife Detected."
A total of 12 signs - six on each side of the highway - have been installed. When an animal triggers the system, two signs for each direction of travel will light up. The warning lights stay on for about one minute.

To detect large game, a cable that emits an electromagnetic field was buried 1 foot deep, 30 feet from either side of the highway, between mile markers 95.6 to 96.6, just east of the Florida River.

The one-mile stretch is a significant migration corridor for deer moving from summer to winter range. It is also where 70 percent of all reported collisions involve wild animals, according to data collected between 1999 and 2003.

"That's a tremendous, tremendous amount of accidents due to wildlife," said Mike McVaugh, a traffic engineer for CDOT. "We've known we had a wildlife problem here for some years. This is a perfect place to be focusing on."
Seven speed radar detectors also have been installed to register motorists' speed both outside and inside the test zone so that drivers' base speed and reaction speed can be monitored. The radar is not being used to identify individual speeders.

"The primary variable we're looking for is motorist behavior," CDOT Environmental Specialist Tony Cady said in a news release. "To test the validity of this system, we need to determine if there's a drop in speed and also whether this is a long-term behavior change, or just something motorists stop reacting to after a period of months."
The entire project, including equipment and installation, cost about $1.2 million. CDOT in Durango received a $150,000 grant to help pay for the project.

It's not being used anywhere else in the country, McVaugh said. Other systems rely on lasers or infrared-motion detectors to activate warning signs, he said, but branches, tumbleweed, small animals and snowplows can all trigger the warning system, he said.

The system installed on Highway 160 uses the same technology that has been used for perimeter security by the military, prisons, airports and some private land owners. Humans can trigger the warning lights if they walk across the underground cable, but the one-mile stretch is not heavily traveled by foot.

There are several driveways along the cable, but the system knows the difference between a car and a deer. It also knows the difference between small animals like squirrels, raccoons and dogs - and signs won't activate for those animals.

McVaugh said too many small creatures live near the highway, and hitting one of those animals doesn't usually cause damage or injury.

"We've tried to eliminate as many of the false positives as we could out here," McVaugh said.

Signs will be displayed at the beginning and the end of the test zone to alert drivers of its presence. The pilot project will undergo three to five years of operation, monitoring and supplemental testing and research before results of its validity can be fully realized. If successful, the system could be installed in other problem areas.

The electromagnetic system will be used in conjunction with physical fences and brush-clearing techniques to reduce animal-vehicle collisions. The problem with fences, McVaugh said, is they disrupt migratory paths.

In addition to installing a mile-long detector, CDOT has cleared 30 feet of brush on either side of Highway 160 between mile markers 97 and 98 to see if that makes a difference in the number of accidents. CDOT will monitor a section of highway between mile markers 99 and 100 as a "control section."
Joe Lewandowski, spokesman for the Colorado Division of Wildlife, said the warning system is a benefit to public safety.

"We've known for years this is a pretty established wildlife corridor," he said. "This will be a great system if it works."
shane@durangoherald.com