Before the first-section groundbreaking, in 1937, the turnpike commission sent workers to assess the former railroad tunnels. In September of that year, a contract was awarded to drain water from the tunnels. After this, workers cleared rock slides and vegetation from the tunnel portals before evaluating the nine tunnels' condition. It was decided that six of the nine former South Pennsylvania Railroad tunnels could be used for the roadway. The Allegheny Mountain Tunnel was in too poor a condition for use, and the Quemahoning and Negro Mountain tunnels would be bypassed with rock cuts through the mountains. The Quemahoning Tunnel had been completed and used by the Pittsburgh, Westmoreland and Somerset Railroad.
