Twenty-two people were injured when a Bangkok-bound tour bus ran off the road and hit a bridge stanchion in Prachuap Khiri Khan province early on Monday, police said.
Pol Lt Nattapong Art-am, a duty officer at Pran Buri police station, said he received a report of the accident about 1am.
Police suspected that Paitoon Boonyakham, the driver, dozed off at the wheel and missed the turn in the road. The bus then mounted the sidewalk, hit the bridge support pillar and overturned.
Twenty-two people were injured. There were no fatalities.
The tour bus, Bangkok licence plate number 15-4892, belongs to the Express Company and was travelling from Phang-nga province to Bangkok.