Police were informed of the accident, on Thepkrasattri Rd, at about midday.
At the scene, officers and rescue workers from the Kusoldharm Foundation found a black Toyota passenger van, registered in Phang Nga with yellow-and-black licence plates, on its side.
The driver, identified by his Phang Nga driver’s licence as Aongart Thongjam, 48, was still at the scene. He remained uninjured from the accident.
His passenger, named as Israeli national Miss Rowan Khadija, 28, had suffered minor injuries.
The van driver, Mr Aongart, told police that the van lost traction on the road due the rain making the road slippery. The van slid in the lanes separated to enter the underpass, then struck the kerb and flipped onto its side.
While in motion, the van also struck one of the lamp posts fitted to the concrete barrier separating traffic entering the underpass from traffic continuing along the road at surface level.
Police had the van removed from the crash site, and said they were continuing their investigation.