Lots of things are required by law in Thailand but most ignore the rules, you are also required to wear a helmet, have working lights, don't drink and drive, use the left hand lane, indicate when turning or changing lanes, stop at stop at stop signs, drive on the left hand side of the road, do not speed, stop at the scean of an accident, don't carry a gun or big knife in public, your lucky if they even have a license, the list is pretty much endless. It summary ALL traffic laws are ignored, the fines are small, and the cops don't do their job.