One sure sign of fall is the escalating number of deer carcasses along Utah highways.

A new study says the human fatalities from animal-vehicle crashes have doubled over the past 15 years. Experts point to urban sprawl overtaking deer habitat. More of these accidents occur during the fall breeding season. Three times more insurance claims are filed from crashes in November than from January to September, industry officials say.

Utah is home to some 300,000 deer, according to 2006 estimates. That means drivers need to be aware of deer populations in their area. Extra caution is needed at dusk and on rural roads, although many deer-vehicle crashes occur on Utah highways.

Utah wildlife authorities have curbed these crashes by building fences along certain sections of highway. Wildlife overpasses and underpasses, such as the deer crosswalk near Jordanelle Reservoir, can significantly reduce deer-vehicle collisions.

Not only does this save deer, it helps reduce accidents that can kill or injure motor vehicle drivers and their passengers. Nationwide, the Highway Loss Data Institute found that 223 people died in animal-vehicle crashes last year. In Utah, 36 people have been killed in animal-vehicle accidents in the past decade, the vast majority involving deer.

It is not possible to fence every road where deer roam. While wildlife overpasses have been highly successful in reducing accidents, they are expensive to design and construct.

While Utah drivers are keenly aware of the dangers posed by deer, elk or moose, this new insurance industry study is an important reminder of the elevated risks of such a collision in November and significant increase of these crashes as deer habitat is swallowed up by urban sprawl.