A police car on a narrow mountain road

On a narrow mountain road a man sees a police car driving uphill backwards.
- Hi guys. Why are you driving backwards?
- Because we are not sure that we will find a place to make a u-turn on the top of the mountain.
After one hour the same man sees the same police car driving downhill backwards again.
- But guys, why are you driving backwards again?
- We found a place to make a u-turn up there.