Interstate 70 in Pennsylvania - History

History

By 1947, present Interstate 70 across Pennsylvania was included in the planned Interstate Highway System. The route from West Virginia split at Washington, with one branch heading northeast to meet the Pennsylvania Turnpike near Pittsburgh and the other heading east, bypassing Pittsburgh to the south (via a planned bypass of Pennsylvania Route 71) to the New Stanton interchange. The piece south from the Breezewood interchange into Maryland was also in the network. The route between US 30 in Breezewood and US 522 in Warfordsburg was originally known as Pennsylvania Route 126. In 1957, preliminary numbers were assigned; the longer route via Pittsburgh (now Interstate 79 and Interstate 376) became the main line of I-70, while the southern bypass (now I-70) became Interstate 70S. A southern extension of Interstate 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 Interstate 76 (east of downtown Pittsburgh), 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.