英语脑筋急转弯 | The Bus Driver Riddle

Riddle:

A bus driver was heading down a street in Colorado. He went right past a stop sign without stopping, he turned left where there was a "no left turn" sign, and he went the wrong way on a one-way street. Then he went on the left side of the road past a cop car. Still - he didn't break any traffic laws.  Why not?

Answer:

He was walking...not driving.