Police were called to the scene, in front of Baan Nai Khlam Noodle House on Thepkrasattri Rd northbound in Moo 1, Srisoonthorn, at 11:35am.
On the left side of the road was a red Honda Wave 125 motorcycle. Nearby was the body of Suriya Petchlamul, an 18-year-old first-year student at Phuket Rajabhat University, registered as living in Sakhu.
Mr Suriya had died of fatal head trauma.
Stopped more than 30 metres down the road was a Bangkok-registered six-wheeled Hino truck.
Police said they found collision impact marks on the left side of the truck, one near the cab at the front, two others in front of the rear left wheels.
The driver, Nuntavorasak Damda, 37, from Loei province, told police that he was driving along the road when he heard a sound of something hitting the truck on its left side. He turned to look and saw a motorbike falling onto the road.
Mr Nuntavorasak said he immediately stopped the truck and went back to check on the motorbike driver, who was already dead.
Mr Nuntavorasak and the truck were taken to Thalang Police Station while police continue their investigation, police reported.
Officers did not speculate whether or not Mr Suriya went under the wheels of the truck or struck his head on the road after falling. His brain was found on the road.
A broken red helmet was found beside the motorbike.
Mr Surya’s body was taken to Thalang Hospital for post-mortem examination and to be handed over to relatives, officers added.