A 61-year-old man was arrested on suspicion of drug-driving and cannabis possession after a serious crash on the A17.
Two people have been taken to hospital after the crash. One suffered serious but not life threatening injuries and one suffered minor injuries.
As previously reported, the collision happened on Kings Lyn Road at around 11.30am just before the Norfolk border.
It caused major delays of more than an hour for many drivers in the area.
Emergency services closed off a section of the road and are still asking drivers to avoid the road.
The road remains closed at the time of writing.