In the late 1950s, US 222 was realigned to a newly constructed bypass carrying US 309 and PA 29, west of Allentown. From the south, US 222 left Hamilton Boulevard and turned north onto the freeway. US 222 terminated at an interchange with US 22, US 309, and PA 29 in South Whitehall Township. The freeway, originally signed as US 309/PA 29/US 222, dropped the PA 29 designation in 1966; in 1968, US 309 was downgraded to PA 309 and US 222 was truncated to end at the current northern termini. By the 1980s, I-78 became part of the freeway that occupied PA 309.