Motorists had to be evacuated from their vehicles after a lorry tanker containing propane caught fire on the M56 motorway in Cheshire.
The vehicle burst into flames on the westbound carriageway near Stanlow, between junctions 14 and 15.
The road remains closed in both directions between junctions 12 and 14 after firefighters managed to put out the fire.
There were delays as a cordon of up to one mile (1.6km) was set up around the burning truck.
Motorists were told to leave their vehicles and move to a safe distance.
Traffic backed up on the motorway and roads network as far as Liverpool and Chester.
Police cut away the central reservation on some stretches of the motorway to allow cars to turn around and exit the road.
Photos posted on Twitter showed motorists on the M56 leaving their sweltering cars to sunbathe outside their vehicles.
Others showed pictures of motorists kicking a ball around on the opposite side of the carriageway empty of traffic.
One driver Tom Jackson told Sky News: “The traffic started coming to a standstill and then there were a couple of small explosions, followed by one large explosion.
“It went up like a giant Bunsen burner.”
Another driver Toby Robinson said: “People realised they weren’t going anywhere. They have been out walking their dogs, stretching their legs, playing football.”
Trains were also stopped on both the Manchester to Chester and Ellesmere Port to Helsby lines, but services later resumed.
The drama began just before 3pm.
The tanker is understood to have pulled over to the hard shoulder as the incident began and there are no reports of injuries.
Motorists have been advised to avoid the area until further notice.