A section of the M1 motorway in Bedfordshire has been closed following a multi-vehicle crash.
National Highways said the southbound carriageway, between junction 13 for Brogborough/Bedford and junction 12 for Toddington, was shut at about 14:00 BST.
Emergency services including an air ambulance were sent, it added.
Northbound traffic has been stopped for the helicopter to leave the scene.
National Highways asked drivers to allow extra time for their journeys and said there were delays of about 45 minutes on the approach to the crash site.
Meanwhile, a section of the anti-clockwise M25 anti-clockwise has also been closed, in Hertfordshire.
Junction 24, for Potters Bar, has also been closed due to a car fire.
Traffic was being diverted via the exit and entry slip roads and there were delays of about 60 minutes.