The Mercedes-Benz involved in the March 13 crash in Ayutthaya that killed two post-graduate students was travelling at a speed of between 215-257kph, police said.
Deputy national police chief Pongsapat Pongcharoen told reporters during a Tuesday briefing on the progress of the investigation that it took the Mercedes only 25 minutes to travel from the toll booth of the expressway on Rama IV Road to where the crash happened, a distance of 52.1km.
The car was seen on CCTV crashing through the toll gate, and 25 minutes later was in Bang Pa-in district where the accident took place. The speed of the vehicle, therefore, would have been between 215-257kph, he said.
The Mercedes sports car, driven by Janepob Veeraporn, 37, rear-ended the Ford Fiesta which was carrying Thanthaphat Horsaengchai, 34, and Kritsana Thaworn, 32, both of whom were post-graduate students at Mahachulalongkornrajavidyalaya University's Faculty of Buddhism. The Ford caught fire, killing the students in the car.
Mr Janepob sustained a knee injury during the crash and was sent to Bang Pa-in Hospital where he reportedly refused to give a blood sample for drug and alcohol tests. Police said if a driver refuses to take a test for alcohol, he or she is presumed to have been drinking.
Pol Gen Pongsapat said police have pressed charges of reckless driving causing death and drink-driving causing death against Mr Janepob.
Police also are set to file additional charges of speeding and driving without regard to safety causing death, the deputy police chief said.
The investigation report involving the charges is expected to be sent to prosecutors by next month, he said. He said police have confidence in the evidence, while relatives of the dead students want police to proceed with the case swiftly.
Ayutthaya police chief Suthi Puangpikul said officers had interviewed 29 out of 41 witnesses.
On March 18, police took Mr Janepob to Ayutthaya Provincial Court to begin 12 days of detention. But his lawyer filed a request for bail on the grounds his client needs further hospital treatment.