One man was killed and a couple left critically injured in the M6 nine-vehicle pile-up near junction 16 for Nantwich.
Many others were injured in the the accident involving two vans, two HGVs and five cars which closed the southbound motorway for most of the day.
All the casualties have been taken to hospital, two flown from scene by air ambulance.
A diversion is in place from junction 18, but all major roads in South Cheshire are experiencing heavy traffic and long delays.
The A54 and the A50 are particularly bad, say Cheshire Police. Drivers are warned to avoid the area and seek an alternative route where possible.
Highways Agency traffic officers and Cheshire Police have been working to free drivers stuck behind the collision at junction 16 of the southbound M6 since the accident happened at around 11.30am.
Traffic is being turned around in the carriageway and being released via Sandbach Services and junction 17 but due to the volume of traffic this is taking some time.
Anyone stuck on the carriageway – or any of the adjoining roads – with urgent concerns about their or someone else’s welfare should ring 999 for emergency help.
Det Chief Insp Brian Roberts said: “We are working closely alongside the Highways Agency and are doing all we can to clear the backlog of traffic and to minimise the disruption that has been caused to the motorway network – and adjoining roads.
“We would like to thank motorists for their continued patience and would like to reassure them that we are doing everything we can to ensure that the carriageway is cleared as soon as possible.”
Anyone with any information in relation to the incident is urged to call Cheshire Police on 101 quoting incident number 338 of 10 December.
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