It has affected the M1 on the southbound carriageway between junctions 42 for Lofthouse and the M62 and junction 41 for Wakefield and Morley.
Roads policing units from West Yorkshire Police and West Yorkshire Fire and Rescue are currently at the scene and have been joined by highways traffic officers for further assistance as well as the air ambulance.
National Highways is advising drivers that the M1 may remain closed southbound for some time and the carriageway is expected to be shut for several hours because a police-led investigation is still being carried out at the scene with the helicopter also still present.
It follows a collision involving two vehicles at around 4.40pm this afternoon (Monday).
There are long delays approaching the closure with both the M1 southbound and the M621 clockwise carriageways becoming congested as a result. Traffic travelling from further afield and heading south are advised to use the A1M.
Police have also started to turn around vehicles in the southbound tailbacks and have asked drivers who are stationary to remain in vehicles and await further instruction.
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