splits from US 422 at a trumpet interchange southwest of the city in Taylor Township. At this point, I-376 becomes a toll road officially named the James E. Ross Highway. I-376 continues southward, still paralleled by PA 18 and the Beaver River to the east. Shortly after entering Beaver County near Koppel, the route connects to its parent route I-76 (Pennsylvania Turnpike) for the first time at an interchange which also provides access to PA 351. Around this area, I-376 crosses into the Unglaciated Allegheny Plateau, where it remains for the remainder of its length. I-376 then passes to the east of West Mayfield and becomes a non-tolled highway again at its first interchange with PA 51 in Chippewa Township, just west of Beaver Falls. The freeway then weaves through mountainous terrain, interchanging with PA 68 in Vanport just before crossing the Vanport Bridge over the Ohio River. It then has its second interchange with PA 18 near Kobuta and continues south from there. I-376 passes to the west of Aliquippa before leaving Beaver County and entering Allegheny County. Approaching PIT, I-376 bends south-southwest and becomes the Southern Expressway, while the Beaver Valley Expressway diverges to the southeast along I-376 Business (I-376 Bus). I-376 circles around the southern edge of the airport, intersecting the western terminus of the Southern Beltway (PA Turnpike 576) at the main entrance to PIT before recombining with I-376 Bus and becoming the Airport Parkway, still four lanes and with a narrow median. Parkway West Now traveling southeast, the route comes to a partial cloverleaf interchange with the Penn-Lincoln Parkway (US 22 and US 30) and Steubenville Pike (PA 60) in Robinson Township. The two US Routes join I-376 here in a partially-unsigned concurrency (indicated only on reassurance markers), continuing east-southeastward bearing the Penn-Lincoln Parkway name, and soon reach an interchange with I-79. From that point eastward, along what was known for many years as I-279, I-376 runs east-southeast through Rosslyn Farms and Carnegie before turning northeast and passing through Green Tree. Entering the city of Pittsburgh, I-376 winds its way northeast to its second interchange with PA 51 at Saw Mill Run Boulevard, which is also part of a spread-out series of ramps linking Banksville Road (US 19) and US 19 Truck. This junction, located just before the freeway passes under Mount Washington in the Fort Pitt Tunnel, features the infamous wrong-way concurrency of the