Seven people were confirmed killed and 20 injured early Monday when their bus crashed into two lorries in Prachin Buri in an accident blamed on malfunctioning brakes.
The bus caught fire after the accident.
Police said the bus was travelling from Nong Khai to Rayong. It rear-ended the two trucks on highway 304 in Na Di district around 2am.
Police said seven people were confirmed dead at the scene, including the bus driver and his relief driver, and at least 20 passengers suffered injuries.
A preliminary investigation found the accident could have been due to malfunctioning brakes on the interprovincial bus.
The bus was operated by 407 Pattana Co, which has a poor safety record.
Trucker Lamsant Phuangphu said he was following behind the bus as it descended the hill road at an unusually high speed before hitting the two lorries in front of it.
Mr Lamsant said he and other motorists stopped to help passengers escape the bus, which caught fire after the crash.
On Feb 26, an accident on the same stretch of road claimed the lives of 17 local government employees from Phon Charoen district in Bung Kan, and injured 40 others. They were on a study trip to Rayong when the bus overturned.
