A11 northbound lane closure between Wymondham and Cringleford
The police said one lane of the A11 northbound remained open but traffic was travelling extremely slowly.
Listeners to BBC Radio Norfolk have reported at least 40-minute delays.
Crews from five Norfolk Fire and Safety Service stations attended the collision.
A spokesperson said the scene was made safe and the casualty left with the ambulance service.
The fire service left the scene by about 07:35.
National Highways said: “There is also a significant spillage of diesel from the collision which will require cleaning and an assessment of the road surface before the road can re-open.”