In Thailand, the liability of a foreigner driving a vehicle is enormous.
In most cases the third party has none or inadequate insurance, and compensation for damages are not paid necessarily by the person at fault but most probably by you...or your insurance, if you have any.

Make sure you have a good insurance for third party (bodily and property) as well as passenger medical cover, plus eventually for own damage as well.

Application Form for Motor Insurance (size: 105KB)
Accident Guidelines: "Relax Zurich" Motor Claim Advice (size: 127KB)