The Pennsylvania Turnpike interchange connecting Interstate 79 and the Southern Beltway will open fully on Friday.

The 19-mile Southern Beltway links I-376 near the Pittsburgh International Airport to I-79 at the line between Allegheny and Washington counties.

The $800 million project was undertaken with the goal of easing congestion on major commuter arteries like the Parkway West, I-79 and Route 50.

“Since opening in October, the Turnpike Commission has seen nearly 8,000 vehicles a day on sections of the Southern Beltway,” Turnpike CEO Mark Compton said. “With all connections at I-79 open, that usage will inevitably increase, which will meet and probably exceed our expectations of 10,000 vehicles on average per day.”

The Southern Beltway operates on the same all-electronic tolling system as the rest of the turnpike, with three toll points along the road. And a new payment method also allows drivers to pay with cash if they choose.

“When they receive the invoice in the mail, there are instructions included as to how to pay with cash by creating a pay slip to take to participating retailers that accept these cash payments,” Compton said.

For a full list of participating retailers and more information on how to use this cash payment method to pay Pennsylvania Turnpike Commission invoices and add funds to existing E-ZPass accounts, see PATurnpike.com/pay-a-bill.

Turnpike officials said the Southern Beltway will also provide an alternative to rural, two-lane roads.

“This was a huge undertaking that couldn’t be accomplished without a large team of dedicated professionals who made this highway a reality,” Turnpike Chief Engineer Brad Heigel said.

From here, commission officials will turn their attention to the next phase of the nearby Mon-Fayette Expressway, with plans to connect Route 51 to Route 837 between now and 2027.