|Is this a temporary or permanent position? proventil coupon free In Yellowstone, for instance, drivers often break suddenly when they spot bison, bears or elk. That can cause fender-benders, and so park managers installed more viewing pullouts. But that leads to other drivers speeding through the area and colliding with the same animals other people are looking at, Ruch said. He said park managers should consider installing overpasses or underpasses to help reduce collisions, better study how roadway changes might affect collision rates, and even consider replacing private vehicle traffic with shuttle buses.