The A1 was blocked just north of Peterborough.
Cambridgeshire police said the road was blocked northbound at Wothorpe/Stamford due to “two incidents”.
Contacted for more information, a police spokeswoman said there had been a collision between a car and a lorry at Wothorpe which was called in at 8.15am.
No injuries have been reported.
The emergency services were at the scene with queues stretching back to Wittering, but the road has now reopened.