how good is the law of canceling driving licence on spot for the offenders ??

This is a good suggestion but there are some traffic enforcers here in our country that abuse their power, they often flag down private vehicles and make up a stupid law just to get their license, while they let the public transports go on the road with a broken and sometimes turned-off headlights.

That's a good idea, let's try it out and see if it works.