There are long delays on the A1 at Wittering after a series of crashes.
No-one has been seriously hurt in the incidents, but there are queues stretching back six miles following incidents on both sides of the carriageway.
Police said the first incident happened at about 11.38am on the southbound carriageway, when a BMW 1 Series hit the central reservation, span, and ended on its roof in a ditch.
A Cambridgeshire police spokesman said two adults and a child were in the car, but had escaped from the BMW. One woman suffered head injuries, but they are not thought to be serious.
Just 40 minutes later, around 12.20pm, a four vehicle accident occurred on the northbound carriageway.
The police spokesman said it was believed the accident had been caused by people slowing down to look at the opposite carriageway where emergency services were working.
It is not thought anyone was injured in the four vehicle crash.
Motorists are advised to try and find different routes and avoid the area.