The Port Authority of Alleghany County (Pittsburgh) PA operates a garage facility where public transit busses are maintained and repaired. The roof of this garage is an open air reinforced concrete parking deck for employee and authority vehicles. This reinforced concrete slab has been subjected to both de-icing salts on the top side and carbonation from the maintenance and repair operations on the bottom side which have caused corrosion damage to the reinforcing steel. The Port Authority has let a contract to repair this parking deck with a desired life expectancy of 25 years.This paper will discuss the condition assessment that was performed on the reinforced concrete slab and the selection of an impressed current cathodic protection system to stop corrosion of the reinforcing steel. The design of the system will be discussed with specific details for both the top and bottom mat of reinforcing steel. The installation of the cathodic protection system will be discussed covering the challenges faced by phasing the work so that maintenance and repair operations could continue in the garage below. And finally start-up and commissioning data will be shown to demonstrate the effectiveness of the cathodic protection system.