As a whole, Thai's are not good drivers. Some do take driving courses, which actually teaches them rules/laws, best practices and courtesy, but for the most part it's from walking, to a motorbike and then to a P/U truck or car, then they graduate to the bus and trucks. There will be very little training and the poor practices from the motorbike stay with them.
Sadly, many foreigners come here and think they can drive like a Thai person. Some have only limited motorbike experience, but rent one and 'go to town' and out for an adventure.
I've had more accidents then my wife, and IMO i'm not a bad driver... Then, I like to sit in the back when she drives and close my eyes. ???????? (otherwise, it drives me crazy)