Pol Capt Thitiwat Asasingh of the Thalang Police was called to the scene of the accident, some 200 metres north of the Heroines Monument, at 1:50am.
Police arrived with rescue workers from the Kusoldharm Foundation and from Srisoonthorn Municipality to find the pickup, an Isuzu D-Max registered in Saraburi, in the middle of the southbound lanes with heavy damage.
The pickup had already been righted by local residents who had rushed to help.
The driver of the pickup, Decha Phothisrisung, 34, was rushed to Thalang Hospital with serious injuries.
Police said that from their preliminary investigation that the pickup was travelling at high speed when Mr Decha lost control. The pickup mounted the central reservation and hit a palm tree and wiped out a kilometre marker before flipping over and coming to rest.
Police have recovered the pickup and are continuing their investigation and have already expressed their intention to charge Mr Decha at least with causing damage to government property.