UPDATE: The accident has been cleared.
A crash involving a tractor trailer on the lower deck of the Fort Pitt Bridge snarled traffic for well over an hour Tuesday.
The accident happened around noon where Fort Pitt Boulevard and Fort Duquesne Bridge, blocking all lanes for over a half hour.
PennDOT asked drivers to avoid the area.
Traffic was heavy on Ft. Pitt Boulevard and Ft. Duquesne Bridge back onto Route 65 and the Northshore Expressway.
As of 2 p.m.
the far two left lanes were blocked by emergency vehicles with traffic moving slowly in the two right lanes.