A semi-tractor trailer became wedged under the 232 Street rail overpass, snarling traffic on Monday afternoon.
The overpass only has 4.4 metre clearance and the trailer hit it while travelling in the left hand lane around 3 p.m.
Traffic was backed up well into 192 Street on Highway One.
Roads around the freeway like 200 Street also suffered serious back ups.
This isn't the first time this overpass has been hit. Several over-height trucks have crashed into overpasses on the freeway in the past.