A man and his dog escaped a campervan fire unharmed shortly after setting off from Woodingdean at the weekend.
The driver stopped on the A26 at Malling Street in Lewes as the fire took hold.
East Sussex Fire and Rescue Service said that it had been started by faulty electrics in the campervan.
Firefighters were concerned about the possibility of a gas cylinder exploding and closed the road briefly.
Watch Commander Dave Washington said: “The carriageway was closed for a short duration for the safety of the fire crew and other road users until it was confirmed that the gas cylinder was out of the vehicle and the fire was under control.
“The cause of the fire was accidental ignition from faulty electrical systems from within the campervan.
“The driver and his dog escaped without injury and crews were on the scene for approximately 40 minutes.”
He said that his firefighters had to wear breathing apparatus as they used foam to bring the blaze under control quickly, preventing it from spreading.
He added that the environmentally friendly 1-in-7 foam that they used can put out flames six times faster than conventional methods but uses six times less water.