A man in his 40s was taken to hospital with serious injuries after a crash on the A17 near North Rauceby on Thursday evening.
The collision involving a blue Vauxhall Corsa and a white Renault Clio happened at around 10.20pm on Thursday, July 16.
The road was closed for several hours before reopening at around 4.30am on Friday, July 17.
Lincolnshire Police are appealing for witnesses to the collision and anyone who has dashcam footage.
Anyone with information should contact Lincolnshire Police on 101 or via email at force.con[email protected] quoting incident number 493 of July 16.