A semitrailer transporting six luxury cars caught fire on the Mitraparp Highway in Nakhon Ratchasima early Wednesday.
The fire destroyed one BMW, two Lamborghinis and a Mercedes Benz, causing damage of about Bt100 million.
Police are probing the cause of fire. They were told the cars' gas tanks were full.
Following a report of the fire at 7.20am, Klang Dong police superintendent Pol Col Manote Kerdkwan and team went to inspect the scene at Mitraparp Highway's 39th kilometre marker and alerted fire engines.
Truck driver Ekkapat Wilamas, 37, told police he was driving the truck uphill with six luxury cars onboard the trailer - two Lamborghinis, one BMW and three Mercedes Benz - when other motorists repeatedly signalled him about a fire on the back of the trailer.
Pulling over, Ekkapat found the BMW, which was loaded last, on fire, and flames quickly spread to the other vehicles, but he couldn't put out the blaze.
The fire also damaged the truck's airbrake tubes causing several luxury cars to slide down off the trailer. Some plunged into a roadside ditch, while others blocked two outbound lanes of the highway and cause a traffic jam.