Bangkok- Khanom bus ran off Highway 41 and crashed into roadside tree injuring about 20 passengers on Monday morning.
The bus from Bangkok was on the way to Khanom district of Nakhon Si Thammarat with 36 passengers when it slid off the highway in Chaya district of Surat Thani at 5.00am, and crashed into tree by the roadside and flipped over.
About 20 passengers were injured.
Rescue and relief officials were alerted and arrived at the scene shortly afterwards. All were admitted to Chaiya and Thachana hospitals for treatment.
Bus driver Somsak Jaijang, 55, claimed a 10-wheeler cut in his right lane too close in overtaking his bus, forcing him to swerve to the left to avoid hitting it.
The bus then slid off and fell into the ditch before striking a tree and flipping over.
But highway police said they suspected his claim as GPS tracking system of the bus showed he drove over restricted speed limit twice before the incident.
Besides they also found no tyre traces that showed the bus driver had applied the braking system before it went off the road.
He was booked for speeding, police said.