Keywords: California, Pituophis catenifer, animal, animals, bull snake, car, cars, collision, collisions, crossing, crossing, crossing, crossings, dead, death, deaths, deer, ecology, effect, effects, erosion, gopher snake, highway, highways, measures, mitigation, mitigation, nature, reptile, reptiles, road, road, road ecology, roadkill, roadkilled, roads, roadside, structure, structures, traffic, underpass, vehicle, vehicles, victim, victims, water, wildlife