The M6 near Lancaster has come to a standstill after two separate collisions within a mile of each other.
The collision happened on the M6 near Galgate at around 8.25am, between northbound junction 33 (Lancaster (South) A6) and junction 34 (Kirkby Lonsdale, Heysham, Morecambe, Heysham A683, Lancaster A589).
Traffic officers closed lanes 1 and 2 after the stricken vehicles blocked the carriageway.
Lane 2 reopened at 9am but lane 1 (inside lane) remains closed.
The Emergency Services attended the scene but it is not known whether anyone has been seriously injured.
Recovery are now on the scene to move the vehicles from the carriageway.
Traffic is slow on the approach, and Highways England are urging people to allow plenty of extra time for their journeys.
Highways expect the carriageway to be clear between 9.25am and 9.50am, with delays of 30 minutes against expected traffic.