In the last four years, cars killed 100 deer in a one-mile section of State Road 73 in Eagle Mountain. And the collisions totaled many of the cars.

Leslie Beck, the Utah Department of Transportation’s Saratoga Springs maintenance station supervisor, was tired of the carnage. The agency pondered wildlife bridges, tunnels or fencing — but it was all expensive and required time-consuming environmental studies. Then Beck came up with what UDOT thinks will be a quick, cheap and first-of-its-kind solution.

The agency this week installed and is starting to test using radar-equipped signs that flash warnings to drivers when deer or other wildlife walk or run into range.

“The signs cost $7,200,” said UDOT spokesman John Gleason. In contrast, wildlife bridges — such as one over Interstate 15 and related fencing completed last year at the top of Parleys Canyon — may cost hundreds of thousands of dollars.

The idea grew out of some nasty crashes.

Beck remembers investigating after numerous pregnant deer had been hit. “The fetuses had been thrown out on the road,” she said. “That just made me think, ‘You know there's got to be something we can do to make this road a little safer.”

At an annual UDOT conference for workers, she saw radar-equipped signs used for other applications — such as warning oncoming cars about curves or pedestrians. She wondered if they could be used to detect and warn about deer, too.

A vendor at the conference said they might, but that no one made such signs. “He came out to the area two or three times” to investigate whether they could work.

The manufacturer, K&K Systems, worked with UDOT to design the signs. They were installed this week, and tests are beginning.

“I think people get used to seeing signs that flash all the time,” Beck said. But the new signs will flash only when wildlife are present. “I think that will get the attention of drivers and make them slow down.”