A chartered bus taking about 50 students of King Mongkut's Institute of Technology Ladkrabang on the way back from Chiang Mai to Bangkok crashed into a roadside barrier and overturned, injuring all students on board.
Four were in serious condition while the rest were slightly injured.
According to police, the bus is among four chartered buses which were carrying about 160 students back to Bangkok from Chiang Mai after completing a voluntary programme.
The incident happened at about 3.00am on Phahonyothin highway in Kamphaeng Phet province.
The bus driver Bancherd Boonchan admitted he lost control of the bus after he fell asleep briefly.
As the bus was about to fall off the road to the ditch on the left side, he swerved to the right instantly, crashing the right barrier and flipped over.
A roadside stall selling gardening furniture was also hit by the bus and damaged.
Police said they booked the driver for reckless driving and admitted all students to Kamphaeng Phet hospital. Four were in serious condition.
Source: Thai Public Broadcasting Service (Thai PBS)