A interesting word---sleeping policeman

Sleeping policeman is a cute word I found in Interent. Guess what it means. Can not do it? OKAY, There is some tips.

1. It's on the street.
2. People tend to slow down when passing it.

Do you think it is the speed detection stuff? No, the answer are wrong. It's the rubber bump on the road to slow down the driver. Is that cute? A policeman sleeping on the road try to make driver slower. HAHA.

There are some pics of sleeping policeman.