In 1984, the Pennsylvania Department of Transportation (PennDOT) was planning to extend PA 145 and US 222 in Allentown. Traffic engineer Samuel D. Darrohh said that Allentown is one of few Pennsylvania cities without a traffic route going through it. After the plan was introduced, he said that motorists might be aided if US 222 were extended along Hamilton Boulevard to connect with the proposed PA 145 corridor. PennDOT originally planned the road as US 222 but AASHTO denied the extension, stating that the route "is not the shortest or best available route between major control points on the system, and therefore, does not adhere to the policies established under AASHTO's 'Purpose and Policy Statement for U.S. Numbered Highways'". In addition, the route did not meet the criteria for a business route. In 1991, it was commissioned as PA 222. PA 145 was extended south of the Lehigh Valley Thruway to the I-78/PA 309 overlap near Lanark.