The closure of the Squirrel Hill Tunnel backed up traffic on the Parkway East to the Forbes Avenue exit this afternoon.
The outbound tunnel will remain closed through 6 a.m. Monday.
Eastbound traffic is required to merge into a single lane and exit at Squirrel Hill-Homestead. The night detour is via Forward, Murray, Forbes and South Braddock avenues.
The daytime detour uses Beechwood Boulevard rather than Murray.
The Pennsylvania Department of Transportation has urged drivers to avoid the area, warning of likely significant delays. The agency urged drivers to consider alternate routes. One option is to exit onto Forbes Avenue in Oakland, go left at South Bellefield Avenue, right at Fifth Avenue and right on Penn Avenue, continuing through Wilkinsburg to the Forest Hills on-ramp.
This weekend's closure is the first of several planned shutdowns as a $49.5 million rehabilitation project continues.
Traffic updates and camera views are available by following a link on the PennDOT District 11 website's home page.
The inbound/westbound tunnel will be open, but traffic may be interrupted briefly for movement of equipment.