National Highways is asking motorists to observe the next diversion after the collision.
Exit the M1 southbound at J6
At the top of the exit slip ‘Waterdale’ flip left on to the A405/St Albans Road/Kingsway North Orbital Road
At the Leavesdon roundabout/A41 Interchange take the first exit on the A41 ‘N. Western Avenue’.
At the Dome roundabout take the 2nd exit persevering with on the A41 ‘Colne Way’/N. Western Avenue’.
At the Berrygrove roundabout take the 2nd exit to entry the M1 J5 southbound entry slip.
https://www.express.co.uk/news/uk/2162216/m1-traffic-live-lanes-closed-crash-watford