Police were notified of the accident at 9:50am, which occurred at the pedestrian bridge in front of Hong Yok Bamrung School on Thepkrasattri Rd in Mai Khao.
Officers from Tha Chatchai Police Station arrived at the scene to find a white 18-wheel Hino truck, registered in Bangkok, carrying a prefabricated house stopped by the side of the road.
Two men were found dead at the scene. Police identified the victims as Myanmar nationals Than Htike Aung and Hein Kyaw.
One victim was found motionless on top of the prefabricated house with severe head injuries, while the second had fallen onto the road below and was discovered face down with serious injuries to his head and body.
According to police, the men had been riding on top of the prefabricated structure to help lift low-hanging wires as the truck passed along the route.
However, when the vehicle attempted to pass beneath the pedestrian bridge, the men were struck by the overpass.
The truck driver, Sittisak Sritincap, told officers he had been transporting the prefab house from Chonburi to Phuket and believed the vehicle was tall enough to clear the bridge.
Rescue workers from the Mai Khao rescue team assisted at the scene, while a doctor from Vachira Phuket Hospital was called to conduct a preliminary examination of the bodies before they were taken for autopsy.
Police have checked the driver for alcohol and reported that no alcohol was detected.
Officers are reviewing CCTV footage from the area as part of their investigation. Police said the driver may face charges of reckless driving causing death, pending the outcome of the investigation.
The case is being handled by investigators from Tha Chatchai Police Station under the supervision of station chief Pol Col Khundet Na Nongkhai.