The M23 is closed both ways due to a crash which happened between junction eight and nine.
A full closure is in place both ways between J8 and J10 near Gatwick Airport, Highways England said.
A spokesman added: “A HGV has collided with the central reservation resulting in debris and a spillage over both sides of the carriageway.
“Highways England Traffic Officers are on scene assisting with traffic management whilst recovery of the vehicle and carriageway clean up takes place.”
London bound traffic is being diverted by the solid black square diversion symbol and should exit the M23 at J10 and head eastbound onto the A264, he added.
The spokesman said: “Follow the A264 until the junction with the A22 and turn north onto the A22. Continue on the A22 until the M25 J6 and join the M25 heading anti clockwise to J7 to rejoin the M23 northbound.
“Coast bound traffic is being diverted by the hollow black diamond symbol and should follow the above route but in reverse.”
Road users travelling northbound for London Gatwick Airport can exit at J10 and travel west on the A2011 to access the airport.
Drivers are being urged to allow extra time for their journey.
Roadworks are ongoing on the A27 eastbound between the junctions with the A280 and the A24 north. Drivers have been warned to expect disruption until 4pm on November 30.
On the rail network buses replace trains between Bexhill and Hastings due to engineering work.
Engineering work is also taking place between East Croydon and Purley, closing some lines.
No Southern services will call at stations between London Bridge and East Croydon via Sydenham.
Tickets will be accepted on London Underground between London Bridge and Canada Water and on London Overground between Canada Water and West Croydon (via New Cross Gate and Norwood Junction).