(Photo by Michael Quinn - Grand Canyon National Park)

Mule deer are the heaviest users of the new wildlife crossing near Oro Valley.

Why did the mule deer cross the road? Maybe because she finally had a safe way to do so.

Last year, a new overpass and underpass that cross State Route 77 near Oro Valley. The $10 million improvement project is meant to help animals safely get to the other side.

The Arizona Game and Fish Department says, so far, mule deer have been the heaviest users of the wildlife crossing. They make up about half the nearly 1,200 animals that have been documented using either the underpass or overpass between April 2016 and January of this year. Other big users include coyotes, javelina and bobcats.

Game and Fish and a coalition of other agencies will study the number of animals using the wildlife crossing for four years, as well as the number of animals killed trying to cross a 6-mile stretch of State Route 77 that borders either side of accommodation.