Thailand's road rules are broadly similar to other left-hand-drive countries, but enforcement patterns and common fines are worth knowing before renting a vehicle.
What actually gets enforced
Helmet use for scooter riders and passengers, licence checks (including whether it's a valid International Driving Permit for the vehicle category), and basic traffic violations are the most commonly enforced items at checkpoints, particularly around tourist areas.
A typical police stop
Checkpoints are common, especially around holidays and evenings — officers will generally ask for your licence and may check the vehicle. Staying calm, polite and cooperative resolves the large majority of routine stops without incident.
Common fines
No helmet, no valid licence, and using a phone while riding or driving are among the most frequently cited offences for tourists specifically — fines are typically paid on the spot or at a local police station, with an official receipt that's worth keeping.
If you're in an accident
Contact your rental company and insurance provider as soon as possible, and where injury is involved, the tourist police (1155, covered in our emergency numbers guide) are a useful English-speaking resource for navigating next steps.