All lanes of the M1 northbound have now been opened after a coach became engulfed in flames at Hemel Hempstead.
Police raced to the scene where the vehicle – which was not thought to be carrying any passengers – was ablaze on the hard shoulder of the northbound carriageway, before the slip road for junction 7 with the town.
Emergency calls came in at around 2.40pm, though the East of England Ambulance Service confirmed it was not been required at the scene.
Fire crews from Hemel Hempstead, Garston and St Albans were on hand to put out the blaze, while lanes 1, 2 and 3 were closed due to thick smoke billowing across the road.
The Highways Agency had warned of delays and urged motorists to avoid the area if possible, but is now organising recover of the burnt-out coach.
The outside lane was opened by 3.30pm and the road was fully reopened by 4.10pm.