Interstate 581 (I-581) is a spur off Interstate 81 into Roanoke, Virginia, United States, completely overlapping U.S. Route 220. It is proposed to be overtaken by Interstate 73. Future I-73 Corridor Signs are marked on I-581; one on the southbound side just after Exit 2.
The I-581 designation ends at the Elm Avenue (State Route 24) interchange in downtown Roanoke, Virginia, where US 220 continues south as the Roy L. Webber Expressway. I-581 was constructed as a six lane highway for its entire length and has not been widened in its history.
Many of I-581's exits are cloverleaf interchanges, which results in weaving. The northern terminus has short merge areas with I-81, particularly the left-lane southbound merge.
Roanoke Regional Airport, Valley View Mall, and the Roanoke Civic Center are all located adjacent to I-581. The Hershberger Road (State Route 101) exit has become a focus of development. In addition to Valley View, two large hotels were constructed in the early 1980s with another group of hotels being constructed from the mid-1990s through the present. In 2002, local CBS affiliate WDBJ constructed its new facility, designed to broadcast in HDTV, on Hershberger Road near I-581.
The Capital Beltway is a beltway surrounding Harrisburg, Pennsylvania in the United States. It is co-designated as Interstate 81 (I-81), I-83, U.S. Route 11 (US 11), US 322, and Pennsylvania Route 581 (PA 581) at various locations along the route. The beltway is primarily located in the suburbs of Harrisburg; however, part of its southern leg passes along the southern edge of downtown. The southwestern section of the highway is named the Harrisburg Expressway. All of the beltway was complete by 1995; however, it was not designated as the Capital Beltway until 1997.
The Capital Beltway begins at the interchange of the eastern terminus of PA 581 and I-83 2 miles (3.2 km) west of Harrisburg in Lemoyne. This junction is colloquially known as the "York split". From the split, the beltway crosses the Susquehanna River on the John Harris Bridge, connecting Harrisburg to its west shore (a colloquialism of the western bank of the Susquehanna across from Harrisburg) suburbs of the city.