A Western Road Hazard -- Falling Cows!

I thought someone was playing a joke when we came across this road sign in the town of Red River. But it is an official New Mexico DOT sign erected to warn motorists that, in addition to rocks, cows could fall onto the road from the hills above. The hillside slopes are free-range grazed and some are quite steep. After rains they get really slick as well. In some states, cows have fallen directly onto cars. The more frequent occurrence is when cows slip off the hillside and fall onto the road injuring themselves, and cars run into them.

I'm not sure what a motorist is to do if a cow comes falling out of the sky.