Officers and Kusoldharm rescue workers were called to the scene, on the verge of the northbound lanes about 800 metres north of the turnoff to Route 4031, at 7am.
On the ground behind the truck was Somchart Nuyang, 46, with injuries to both legs and his left arm.
His black Honda dream motorcycle had sustained heavy damage, and the steel-reinforcement bar fitted to the back of the Bangkok-registered white Hino truck emblazoned as the property of Tanin Transport Co Ltd had a heft dent.
The truck driver, 26-year-old Sittipong Hassin, said he was returning to Surat Thani after delivery goods to convenience stores in Phuket when he parked beside the road.
"I parked on the street then I heard a screeching sound. I got out and saw that a motorbike had hit the back of the truck and its rider on the ground injured - and I called the police," he told officers.
No reason for pulling over and parking in the emergency lane was given.
Sub Lt Suphorn Muangkai of the Thalang Police reported that would complete his investigation before drawing any conclusions or pressing charges.