Two people were taken to hospital with “serious” injuries following a collision on the A59 near Tarleton.
The smash forced the closure of the busy road between Preston and Southport, with traffic stuck in long tailbacks in both driections.
Police say the incident was reported at around 5.25pm today and the road was still blocked after 8pm.
A spokesman said: “It is a serious injury road traffic collision involving two vehicles.
“There are two casualties with serious injuries and they have been removed to hospital.”
The collision happened on Liverpool Road between the B5247 Carr House Lane and Coe Lane.