Transportation Minister Blair Lekstrom was expected to mark the milestone by walking across the span on Thursday afternoon,
The 3.3 billion dollar project was launched in August 2008 to replace the old Port Mann bridge, which is currently congested for an average of 14 hours a day.
Once all 10 lanes are complete, the 850-metre span cable-stay structure will be the widest in North America — as well as one of the longest.
The government says when the first eight lanes of the toll bridge open next year it will cut commute times significantly, but not everyone is convinced.
Gordon Price is director of SFU's City Program says it may cut congestion for a while, but eventually traffic will build to the point where the new bridge is congested as well.
"I am not sure how long it will take. But the bridge will generate more traffic. The highway, the South Fraser Perimeter, the Golden Ears, the Pitt River, all the arterials that have been widened — they are building car dependence as fast as they can"
A plan to have a fleet of dedicated express buses cross the Port Mann Bridge in a special HOV lane has already been scrapped by TransLink because it has no cash to pay for a public transit service over the bridge.