The Fire Service had several calls to a car on fire on the M5 Southbound from Junction 28 Cullompton to Junction 29 Sowton.
One fire appliance from Cullompton and one fire appliance from Middlemoor Exeter were sent at 8.15pm.
A fire service spokesman said: "Fire crews confirmed a fire involving the engine compartment of a car parked on the hard shoulder. Fire crews extinguished the vehicle using one hose reel jet. The cause of the fire is believed to be accidental."