Police said they had been called to the northbound carriageway near junction 39 at around 3.05pm along with the fire service.
A grey Volkswagen Golf has overturned, blocking one lane.
Highways England said the car had left the carriageway between the junctions with the A639 and the M62.
It warned that delays were building between junctions 39 and 40, close to Pontefract, as a result.
The scene is expected to be cleared between 4.45pm and 5pm.