Emergency services were called to the collision involving a van and a lorry on the westbound carriageway between Junction 1 for Featherstone and Junction 2 for Wolverhampton, at around 10pm on Tuesday.
Firefighters, police and ambulance crews were all at the scene.
Delays continued as the car was righted and moved to the hard shoulder, with lanes two and three remaining closed as the spillage was dealt with, and the queue stretching back over a mile.
A spokesperson for West Midlands Ambulance Service said: "The van, which suffered front end damage, rolled over after the collision but the driver was able to get out himself before ambulance crews arrived.
"He was assessed but discharged with minor injuries. The lorry driver was unhurt.
"An ambulance and a paramedic officer attended the scene."
All lanes were reopened about an hour later.