Calgary, Alberta – Roadside wildlife warning signs work, but they’re not always being used correctly to prevent collisions, according to new Canadian research. Collisions between deer and vehicles pose a serious danger to drivers.

In the research, published in the Wildlife Society Bulletin, Canadian scientists examined locations and time periods of high rates of deer-vehicle collisions to assess the effectiveness of warning signs to prevent fatalities.

Property damage resulting from deer-vehicle collisions is estimated to cost $200 million a year in Canada and over $1 billion in the U.S. Ninety per cent of collisions are fatal to the deer and 65 per cent cause injury to humans, but the team found that 77 per cent of Canadian and U.S. transport agencies rarely, if ever, employ prevention strategies for new projects, and when warning signs were used, they were often placed arbitrarily.

“When you consider the amount of collisions that take place, it is treated almost as common knowledge that deer-crossing warning signs don’t work,” said Dr. Rob Found, of the University of Calgary. “Indeed, with all the technology available to us, there is skepticism that a sign stuck in the ground is able to reduce collisions with deer and save society millions of dollars.”

The team focused its study on Edmonton, which borders dense forestry, and used collision statistics from 2002 to 2007. After identifying 28 “hot spots” within the city limits, the team placed warning signs in 14 of the 28 locations. The results showed that drivers altered their speed for up to 1.6 kilometres after passing a warning sign.

The results also showed that while there had been 139 collisions the previous year, the rate dropped to 78 collisions city-wide once the signs were in place. The researchers suggested that because warning signs are a cheap and easy prevention tool, they have become overused, but when placed selectively to target collision hot spots, they can still be effective at reducing collisions.

“Prevention strategies are not only a matter of saving the lives of both humans and deer, but also finding ways for deer and humans to share the same habitat,” Found said. “Our study showed that warning signs really do reduce deer-vehicle collisions, but we will require a follow-up study to determine if drivers remain responsive to these signs in the long term.”