The impact of the collision was such that the car's driver door and roof were lying several metres away from the crushed car.
Traffic was diverted with the help of fire crews and police took photos of the scene, and the injured man who had been driving was taken away by ambulance.
"I thought he was in trouble, but he was breathing," Mr Pearce said. "Everyone was pretty helpful but I just concentrated on the occupants, trying to make them stay calm."
Acting Senior Sergeant of the Eastern District Road Policing Group Clint Adamson said exactly how the accident had occurred would be investigated.
"The car has been heading towards Hastings from Napier and for whatever reason... the truck has pulled across the front of the car," he said. "Obviously there has been a massive collision and the driver of the car is critically ill at this stage."
He asked that drivers pay attention to what was happening around them and be sure the way was clear.
"Two vehicles should never end up on the same stretch of road. Someone has made a mistake and that is part of the investigation."
Last night the man was in a coma in Hawke's Bay Hospital.
In the earlier accident yesterday, Mr Langley died when the Toyota Hilux he was transporting logs in, crossed the centre line on Evenden Rd, coming to rest in a roadside drain.
He had been travelling east after the SH50a roundabout, and was found at the wheel when a passing motorist saw the vehicle on the side of the road and stopped to check.
Police were unsure how or why the vehicle had crossed the centre line.
"Police cannot comment at this stage as to the factors that contributed to the accident, as the investigation is in the early stages," a police statement read. Members of the public who witnessed the incident are asked to contact Constable Paul Bailey of the Hastings Strategic Traffic Unit on 06 8730500.