Thanachai Rungroj told Buraphawithee Expressway police that he fall asleep at the time when the vehicle hit the rear of a car on its way from Bangkok to Pattaya on the Bang Na-Bang Pakong elevated tollway at 5.30am in Bang Bo district.
Pol Lt Col Natthawat Pungpho of the expressway police station said seven passengers were slightly injured and sent to Ruamchai Pracharak Hospital.
The van normally serves the route between Central Department Store at Lat Phrao and Rattanathibet Housing Estate but it was switched to operate from Mor Chit to Pattaya on Wednesday.
The driver was charged with reckless driving, Pol Lt Col Natthawat said.
Public passenger vans servicing Bangkok and inter-provincial lines have been a target of complaints by passengers.
Land Transport Department chief Asdsathai Rattanadilok Na Phuket said on Wednesday that transport officials were directed to strictly check the condition of all vans and drivers in Bangkok and other provinces.
He admitted that the department had received complaints from passengers covering several issues from driving too fast to rude service.
Those found will be fined and could see their driving licence suspended, the official warned.