The incident happened near Kilometer marker 47 of the motorway from Bangkok to Chonburi shortly after midnight.
Injured seriously are Miss Pama Sarah Loh Mae, 25, Miuss Calinawan Monnaliza Kay, 24, and Miss Mae Dumaguin, 25. They were rushed to Chularat 11 and Bangpakong hospital by highway rescuers.
Highway division 8 police officer Pol Lt Col Supakit Kongam said the police were alerted of the incident at 00.30 am Saturday that several people were injured in the car crash on the motorway near Km 47 marker.
A black Honda Civic car was parked on the highway shoulder with its right rear badly damaged from the collision, and a Toyota pickup truck parked nearby with the front smashed.
Investigation later revealed that the three Filipinos came in the Honda car with another Filipino male friend, Keith Narungahon, 26, to Pattaya.
But as the car was near Km 47, its rear right tire burst forcing the driver to park on the motorway shoulder to have the tire replaced.
Another Thai Samaritan passing by stopped his vehicle to help them replace the tyre.
As Keith walked towards the Samaritan’s car in front to get traffic signs to place at the rear of his Honda car to warn coming vehicles, an unaware pickup truck came close at high speed and crashed into the Honda car injuring the three girls standing at the rear.
The pickup truck driver was not injured but was in shock state.
Keith told police he was driving his friends from Suphanburi to Rayong for night tour but the tire burst while passing Chonburi.