The A6 was closed for several hours and an air ambulance called following a three-car crash.
Police and paramedics were called to the scene on the A6 Scotforth Road, near Lancaster City Garages, at around 12.45pm.
Three vehicles had collided, and six people had been injured, including a woman who suffered a broken arm.
The road was closed in both directions for several hours, leading to heavy traffic congestion in the area, but has now been reopened.
Lancs Roads Police tweeted: "Many thanks to members of the public for their patience due to road closures on the A6 at Scotforth.
"The scene has now been cleared and the road re-opened."