Motorists were being told to expect delays after a road collision the A47 at Thorney,
Delays were between the A141 March Road and B1167 New Cut.
Traffic was able to pass slowly, according to the AA.
Cambridgeshire police said a woman was injured but details of her injuries remain unclear at this stage.
Police were called to the incident at 1.45pm.
A spokesman said at least two vehicles were involved and that ambulance crews have attended.
The road has now fully reopened.