An articulated lorry is reported to have left the carriageway.
Eyewitnesses describe a major emergency response involving police helicopter, up to a dozen police cars, fire and other services.
The witness described the lorry travelling from West Bridgford over Lady Bay Bridge toward Meadow Lane was involved in a collision.
Nottinghamshire Police will issue an update soon.
AA Roadwatch said:
‘Road closed and very slow traffic due to crash, lorry involved on A6011 Lady Bay Bridge both ways from Edward Road to A6011 Meadow Lane.’