The famous “Colorado falling bear,” a black bear who was photographed falling out a tree after being tranquilized, has died. The photo, which went viral in recent days, depicted the 280-pound bear—who had wandered onto the campus of the University of Colorado at Boulder—descending peacefully into a soft mat set up by authorities. But just days after the bear was released into the wild, it was struck by a car and killed. How can we reduce these kinds of accidents?

A 2007 article in the Journal of Mammalogy may hold clues. The authors studied the effect of roads on habitat quality for black bears. Roads play a complex role in bear habitats—they can facilitate travel or provide food sources, but they also increase the risk of interaction with hunters and poachers (and, of course, vehicles). Moreover, scholars don’t fully understand how road use differs by age and sex. But according to the authors, who studied 118 bears over a 20-year period, one thing is clear: Bears avoid areas near gravel roads more than areas near paved roads. The authors caution that more research is needed before we can understand how gravel road avoidance affects bear survival, but in any case, it seems worth noting that the road where the falling bear was struck is apparently paved