An experimental wildlife-detection system installed nine years ago on U.S. Highway 160 east of Durango has fallen into disrepair and is no longer operational.
The $1 million system was designed to detect wildlife, such as deer and elk, on either side of the road and alert drivers of potential hazards.
But after several years of research and making repairs, the Colorado Department of Transportation has largely given up on the technology in favor of cheaper fencing and wildlife tunnels to reduce animal/vehicle collisions.
“It was a lot more maintenance than we were anticipating,” said Mike McVaugh, transportation director for Region 5.
What’s more, the 40-inch by 60-inch lighted signs that read “Wildlife Detected” had little effect on driver behavior, McVaugh said.
“The main focus of this study was: Can we get drivers to behave and actually listen to this and slow down?” he said. “When we were done doing this and collecting that data, we weren’t seeing them slow down.”
Many drivers said the system didn’t work: Signs would light up when no wildlife was present, or they wouldn’t light up when deer and elk were visible on the side of the road. CDOT also made updates to the system to eliminate “false positives,” including those caused by drivers who passed over detection wires underneath their private driveways.
The system was developed by Senstar Corp. and installed in 2008. It uses the same technology as perimeter security systems at airports, prisons and military bases.
Cables were buried 9 inches underground on both sides of the highway – about 30 feet from the roadside – that emitted a small electromagnetic field. If the field was disrupted by wildlife passing through, signs lit up on the side of the road with an image of a leaping deer.
CDOT installed a dozen signs, six on each side of the highway, and specific signs lit up based on where wildlife was detected.
The system covered a one-mile stretch of the highway, between mile markers 95.6 and 96.6, just east of Elmore’s Corner and the Florida River.
Unlike airports, prisons and military bases that can monitor perimeters 24/7 and make repairs as needed, CDOT hoped to install the system and largely forget about it. Instead, it required constant repairs as a result of critters chewing through detection cables, McVaugh said.
The manufacturer told CDOT the cables needed to be installed in sand bedding. When burrowing creatures hit the soft ground, they tended to stay there and bite into the wires, he said.
“We’re used to putting cable in the ground and protecting it,” McVaugh said. “We couldn’t do that here.”
The repairs were costly and time-consuming, he said. CDOT fixed it a few times, but “then it just got prominently worse and worse and worse,” he said.
The system hasn’t functioned for two or three years, he said.
CDOT plans to eventually remove the wildlife detection signs. But it’s possible the highway department will maintain a small portion of the detection zone near the west end, where it abuts deer fencing. It makes sense to use the system near the end of fencing where it’s likely animals will cross the highway, McVaugh said. It will be easier to maintain a tiny section compared with a mile of wire on both sides of the highway.
Overall, it is more effective and cost-efficient to install deer fencing and underground tunnels than to line miles of highway with the electronic detection system, he said. In addition to the $1 million price tag for installation, the wildlife-detection system cost money for upgrades and repairs – including a lightning strike that disabled part of the circuitry. But it was worth researching the electronic-detection system, he said.
CDOT continues to study migratory patterns and identify areas that are most prone to wildlife crossing, McVaugh said. That helps determine where resources are best spent, he said.
A recent plan calls for 24 wildlife underpasses along a 20-mile section of Highway 160 east of Durango. About eight underpasses will be designed for large wildlife, and 16 will accommodate smaller animals, such as foxes, coyotes and bears.
“For the money we spent on one mile, we could do several miles of fencing, we could do underpasses, we could do overpasses,” McVaugh said. “Cost-wise, we could have a much greater benefit doing another system versus this.”