There are many cause of car accident in Thailand. At the present there are many vehicles in Thailand that number of accidents increase. There are many cause of car accident in Thailand, for example; the bad roads is not development .The lack of driving experience and driving too fast. Sometimes the driver drinking alcohol or less relaxing cause is falling asleep, and other factors as bad weather because is torrent or foggy in thick, the driver don't check car problems. all of these can cause car accidents. Therefore, the driver should be careful and check the vehicles before leaving home.