Eighteen people were injured when a 'sleep-deprived' bus driver ploughed through traffic in Thailand.

Motorist Boonmee Janphan, 59, was driving along the Rama II Road in the capital Bangkok and had to stop as traffic built up on Tuesday morning September 26.

While trying to slow down, he reportedly stepped on the accelerator and mowed down several vehicles in front of him.

Traffic camera footage shows how the large vehicle rolled forward several feet, bulldozing the smaller cars in its path.

Bang Mod Police Station officers said they received a report of the pile-up, and rushed to the scene at Rama II Soi 4 with medics and a rescue crew.

Cops said 14 cars were damaged while 18 people were injured and given first aid. The wounded were rushed to four nearby hospitals for further medical treatment.

Wichak, 37, a pick-up truck driver involved in the accident, said: 'My vehicle was the first to be rear-ended. I didn't understand what was happening, and before I knew it, my truck was already on top of another car.'

The multiple collision caused a severe traffic jam as authorities cleared the wreckage.

Boonmee had blamed the accident on malfunctioning brakes - a claim refuted by his employer Thai Smile Bus.

In a statement, the company said that Boonmee had been 'sleep-deprived and momentarily inattentive'. When he felt the bus moving during heavy traffic, he mistakenly pressed on the gas pedal and lost control of the vehicle, it said.

The statement continued: 'Thai Smile Bus Company confirms that the electric bus has no malfunction in both the electrical system and the brake control system. It has been confirmed that the cause of the collision was not caused by a brake malfunction because the buses undergo daily checks to ensure they are roadworthy.'

Boonmee will face the 'maximum penalty as per company rules', Thai Bus Smile said.

Meanwhile, police officers from the Bang Mod district station said they were conducting a separate investigation to prosecute Boonmee.

Thailand has one of the world's worst road safety records. Ministers have set the goal of reducing fatalities from 32.7 deaths per 100,000 people to 12 per 100,000 people by the year 2027.

However, a lack of road safety education in schools along with notoriously easy driving tests, police failures to enforce road laws, and chronic under-investment in infrastructure, all appear to hamper the efforts.