Three people, including two police officers, have been injured in a crash involving a police car and two lorries.
It happened on the A1 at 11.23am on Wednesday morning, at Colsterworth near Grantham, when a police vehicle crashed with two HGVs.
Two officers in the police car were taken to hospital with injuries, as was the driver of the second HGV.
None of the injuries sustained in the accident are believed to be life-threatening.
The road was closed in both directions during the early afternoon, but the A1 northbound carriage has since reopened.
The road southbound is likely to be closed for some time, and police are asking people to plan alternative routes away from the incident.
A spokesperson for Lincolnshire Police said: “We are grateful for the patience of those who have been affected and ask that if you are able to, please avoid the area.”