PennDOT is closing Allegheny Boulevard from 8 a.m. to noon Saturday for emergency tree removal work.
The boulevard will be closed between Nadine Road and Washington Boulevard, which spans Penn Hills and the city of Pittsburgh.
The closure could be lifted earlier pending completion of the work.
Motorists are advised to use Washington Boulevard (Route 8); Bennett Street and Frankstown Road (Route 380); or Coal Hollow Road and Sandy Creek Road (Route 130) as the detour route.