Mackin provided design and construction phase engineering for the improvement of U.S. Route 22, Section B01 through the commercial area of Murrysville. The purpose of the project was to improve Route 22 from an unsafe, substandard three-lane highway to a safe, multi-lane (four to six lanes), semi-controlled access highway. Traffic engineering services included a combined signing and pavement marking plan, a closed-loop traffic signal system, and extensive maintenance and protection of traffic. Revisions to the three existing traffic signal installations and construction of five new traffic signal installations were incorporated in the closed-loop system. Effective phased maintenance & protection of traffic involving temporary traffic signals and detours were incorporated to safely and efficiently carry traffic with a minimum of delay and to permit left turns during construction.