While vans use diesel. Both fuels are freely available throughout Thailand and prices generally range between Baht 14. Fuel stations are plentiful and most of the larger ones accept major international credit cards. In more remote locations cash will be required. Road Rules Thailand uses the left-hand system.
Police regularly check motorists' speed.
Wearing of seat belts is compulsory and drunk driving laws apply. All insurance is invalid if drivers exceed the legal alcohol limit. While there are numerous car rental companies as well as comprehensive self drive holiday packages available it is worth noting that rentals from many of the smaller companies are not covered by insurance and you will be liable for any damage to the vehicle regardless of who is at fault. Several Internationally recognised car rental companies either have offices in Thailand or have allocated agents here. While these companies are generally more expensive they do tend to offer better insurance coverage.