This is the dramatic moment a passenger jumps from an out-of-control truck as it rolled backwards down a slope in a car park.

The vehicle was leaving the mall parking lot in Bangkok, Thailand, on August 23 when it suddenly stopped at the top of the exit ramp and began sliding downwards.

It then accelerated and came barreling towards the car of mall-goer Siriyakorn Saelim, who quickly backed up to avoid a deadly crash.

Dashcam video shows how the truck's terrified passenger risked his life and flung himself from his seat during the ordeal.

The truck finally stopped when it collided with a stone column.

Siriyakorn said: 'I was only seconds away from getting smashed directly by a truck. Luckily nobody was hurt after what happened.'