Emergency services were called to the A6 on the roundabout near to the Holiday Inn Express hotel at Bamber Bridge at around 10.30am today.
An eyewitness said: “A car was on its roof and people were trying to get someone out of the vehicle.
“It was on the A6 just by the exit sliproad from the M6 junction 29.”
A police spokesperson said: “We don’t believe at this stage that there have been any serious injuries.
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“It involves a 62-year-old woman and an ambulance is on its way.”
The incident left traffic queuing down the motorway sliproad and on the A6 at the roundabout.