
The accident happened at about 4.30am on the inbound Saraburi-Lop Buri Road in Chalerm Phrakiart district.
The pickup truck was driven by Private First Class Chirasak Charoentham, who died behind the wheel.
The two passengers killed were identified as Private First Class Montree Tambut and Private First Class Surat Hiranthat.
The dead soldiers were from the Saraburi-based Army camp.
The injured civilian was identified as Apidej Sienkhunthod. He told rescuers that they were returning from a pub.
The truck driver, Ruay Piangta, 57, said he was heading to a cement plant in Saraburi and he felt sleepy so he parked on the roadside with the truck’s emergency lights on. A moment later, the crash happened, he said.