Witness Phataraphon, 24, said he was going to his girlfriend's house.
He passed the area where the accident occurred but saw the pick-up on the wrong side of the road coming towards him. He had to veer suddenly to stop becoming a victim himself.
But within seconds the accident occurred at the bend.
Suphanburi police said that clearly the grey pick-up was in the wrong.
A Thai man was driving and not a Burmese national as was rumored on social media, police confirmed.
They could not say yet whether the man was drunk. They were awaiting blood tests carried out on him at the hospital where he lays injured.
He is likely to face a charge of negligent driving causing death.