Officers led by Maj Narong Muangduong of the Vichit police arrived at the scene with Kusoldharm rescue workers at 6:20pm.
They found Thanapat Songserm severely injured, lying near the rear-left wheels of the truck. He was still in his Vichit Songkram School uniform, and had suffered a broken leg and broken neck.
Despite efforts by rescue workers, Thanapat died en route to Vachira Phuket Hospital.
His mother, Patchanee Songserm, 42, suffered only minor injuries, but was also taken to Vachira hospital for treatment.
Witnesses told police that Ms Patchanee was driving westbound with her son on the back of the motorbike and a Phuket-registered Concrete TPI cement truck following behind.
“Both vehicles stopped at the red light in front of Makro. When the light turned green, the motorbike collided with the front wheel of the truck and crashed to the ground,” Maj Narong explained.
“Thanapat fell onto the road and was crushed by the rear wheels of the truck.”
Maj Narong confirmed that he had yet to file charges against any party over the incident.
“We have impounded the truck while we continue our investigation,” he said.
“We have to question the truck driver and witnesses further before deciding who should face which charges.
“And we will wait until the mother is in a condition fit for answering more questions.”