A stretch of the M1 northbound will close overnight for four nights so that repair work can take place after a lorry overturned this morning.
The carriageway and safety barriers were damaged during the incident between Junction 8 for Hemel Hempstead and Junction 9 for Redbourn, in which a heavy goods vehicle overturned across all four lanes.
The driver was not injured.
Commuters faced gridlock across Dacorum this morning as lanes were closed to allow the vehicle to be recovered and spilled diesel to be cleared up, after police were called at 5.53am. The motorway was fully reopened by 11am.
Over the next four nights work will take place between 10.30pm and 5.30am and will include repair of the safety barriers and associated technology, rebuilding of the central reservation and resurfacing of the carriageway.
For live traffic information visit www.highways.gov.uk/traffic or follow @HAtraffic_east on Twitter.