Traffic lights

Nowadays when we walk along the street we can see the traffic lights everywhere their names are red light yellow light and green light
and also we can meet the traffic policeman standing  nearby
If people walk into the wrong way the policeman will  stop you immediatelly
if someone walked slowly like old man or disabled people，maybe the policeman could stop the car
All car should stop at the zebra crossing.

Usually when people meet the yellow light，they will run quickly