Interstate 70 in Pennsylvania

Section of Interstate highway in Pennsylvania, United States

the former Pennsylvania Route 70

Interstate 70 (I 70) is a state highway that is located in the Commonwealth of Pennsylvania in the United States. It runs east to west across the southwest part of Pennsylvania and serves the southern fringe of the Pittsburgh metropolitan area. About half of this route is concurrent with I 76 on the Pennsylvania Turnpike, which is a toll road. This is the oldest segment of I 70 in Pennsylvania, having been completed in 1940, and is only one of two segments of I 70 that are tolled, with the other being the Kansas Turnpike. I 70 is one of only a few Interstate Highways to have a traffic signal—in this case, with U. S. Route 30 (US 30) in Breezewood, where it leaves the Pennsylvania Turnpike and heads toward Maryland.

Two segments of I 70 in Pennsylvania are not designed to modern Interstate standards: a 37 mile (60 km) segment from Washington to New Stanton and the aforementioned half mile (0.5 mile (1 km)) signalized segment in Breezewood.

I 70 enters Pennsylvania from West Virginia, coming into Donegal Township, Washington County. The highway continues northeast as a four lane freeway with a standard size median up to Interstate Highway standards through rural areas of woodland and farmland, coming to its first junction at a partial cloverleaf interchange with State Route 3023 (SR 3023), to the southeast of unincorporated village of West Alexander. Past this junction, the freeway begins to parallel US 40 on the northwest side of the road, before it enters a series of winding curves. From here, I 70 heads east to meet a weigh station and a welcome center in the eastbound direction, as well as an interchange with SR 3024 connecting to Pennsylvania Route 231 (PA 231) via US 40 in the borough of Claysville. The freeway curves to a more east northeasterly direction, where it briefly passes through the borough limits of Claysville, before briefly reentering Donegal Township. I 70 enters Buffalo Township, where it soon meets a pair of right in/right out ramps connecting to PA 221, which serves the unincorporated village of Taylorstown to the northeast, in adjacent Blaine Township. The freeway comes into North Franklin Township before crossing into Canton Township at its partial interchange with US 40 which lacks a westbound entrance; the interchange is adjacent to the Washington Crown Center shopping mall located to the southwest of the interchange. The route between US 30 in Breezewood and US 522 in Warfordsburg was originally known as Pennsylvania Route 126 (PA 126). In 1957, preliminary numbers were assigned; the longer route via Pittsburgh (now I 79 and I 376) became the main line of I 70, while the southern bypass (now I 70) became Interstate 70S (I 70S). The original alignment is now known as Old 126 or Breezewood Road. The section of present day I 70 between PA 519 near Washington and New Stanton was built as a four lane divided highway known as the "Express Highway"; this road was assigned the temporary PA 71 Alternate (PA 71 Alt.) designation in 1957 and would be designated as I 70S following the completion of additional connecting roads in the Interstate Highway System. On July 15, 1960, I 70 was designated onto the Penn Lincoln Parkway. A southern extension of I 79 (which had previously only run from Erie south to Pittsburgh) to Charleston, West Virginia, in 1963 resulted in changes to I 70. On February 26, 1964, as part of the formation of I 76 (east of Downtown Pittsburgh), the American Association of State Highway and Transportation Officials (AASHTO) approved a rerouting of I 70 along I 70S. The former I 70 became I 79 from Washington to downtown Pittsburgh and I 76 to and along the Turnpike to New Stanton. This brought the routing of I 70 to its present form.

In 2011, the Pennsylvania Department of Transportation (PennDOT) began preliminary work for a total reconstruction of I 70 between the West Virginia state line and New Stanton. Approximately $500 million will be spent on this 58 mile (93 km) segment of highway in order to improve it to modern Interstate standards, half of which will be spent redesigning eight interchanges. Other planned improvements include six overpass replacements, a new roadbed, a wider median, electronic ITS signage, and widening the I 70/I 79 concurrency in Washington to six lanes. Two noteworthy interchange projects will occur in conjunction with the I 70/I 79 widening. Underway is a reconfiguration of the east/south split between I 70 and I 79, which will eliminate the one lane, low speed loop ramp from I 79 northbound to I 70 westbound, replacing it with a two lane, high speed flyover ramp. Preliminary design work has also been completed for a redesigned interchange between I 70/I 79 and Murtland Avenue (US 19), and involves replacing the existing substandard cloverleaf in favor of the first diverging diamond interchange in Pennsylvania.