Police closed a section of the A15 after a serious crash near Bourne on Monday morning.
An Audi A3 and a Mini Cooper were involved in the collision. An air ambulance is at the scene after someone was seriously injured.
A section of the A15 near the B1177 junction in Morton has been closed in both directions from Haconby Crossroads to south of Morton.
The road is expected to remain closed for some time. Lincolnshire Police is advising people to avoid the area.
A spokesperson for EMAS said: “We received a call at 10.54am this morning to the A15. The caller reported an RTC. We sent the air ambulance, a paramedic in an ambulance car and two crewed ambulances. We transported one patient to Peterborough City Hospital.”
According to AA Traffic the accident has caused the road to be blocked and queueing traffic.
Any witnesses to the crash should contact police on 101 quoting incident 145 of December 17.