What's this machine on the road side?

I learned a saying here although I can’t remember it precisely:
路上有三個寶貝:女生,老人及老女生。

The police are retarded here. A private company could enorce the law a hundred time better and make 50x more revenue with stationary cameras at traffic lights, speed tracking on ETC and undercover cameras equipped vehicles on the road. The traffic light enforcement is the easiest .
But it won’t happen because…Voters

Sure.