From the North Hills to the South Hills, drivers can expect to see traffic backups starting this weekend as two major PennDOT projects get underway along McKnight Road and along Route 51. 

Starting tonight, a crossover is being put into place along Route 51 in Pleasant Hills between Coal Valley Road and East Bruceton Road, reducing traffic to a single lane in each direction. 

PennDOT says that traffic headed towards the city of Pittsburgh will only be able to make left turns at intersections where there are traffic lights and the crossover expected to be in place through mid-June.

The one-mile stretch of road being worked on between now and June is part of a $20 million project to perform numerous different work along Route 51 stretching from Peters Creek Road in Jefferson Hills to Stewart Avenue in Pittsburgh's Overbrook neighborhood.

Drivers in the North Hills are going to be impacted by a similar project starting tomorrow night along McKnight Road.

A section of McKnight near Babcock Boulevard is already down to five lanes but by Saturday night, it'll be down to just one lane in each direction.

For drivers headed southbound towards the city of Pittsburgh, a crossover will take place just past Ross Municipal Drive.

One lane of traffic in each direction will use the northbound lanes of the road and then traffic will cross back over to normal lanes shortly after crossing the bridge.  The crossover work is being implemented so that crews can perform major work to the bridge's deck and barriers.

There are a lot of moving parts, so there's no definitive end date yet, but it looks like the work will wrap up early in the summer.