Long before modern paved highways, rough muddy wagon roads provided the only inland access to Oregon's coast, and travel north or south often followed the beach at low tide. Construction of a continuous coastal road called the Roosevelt Military Highway began in 1919, and construction of the Yaquina Bay Bridge began in 1934 as part of a Works Progress Administration project. When completed in 1936, the bridge provided a final link in Oregon's coastal highway system, while related highway projects in Washington and California helped create a continuous roadway from Canada to Mexico that is now called U.S. Highway 101. Oregon's rocky headlands, mudflats, bays, and rivers made the coast highway difficult to build, and progress came slowly county by county. Designed by Conde B. McCullough, the Yaquina Bay Bridge cost $3,301,016 and uses both steel and reinforced concrete arches. The project employed 220 men to pour more than 30,000 cubic yards of concrete and fabricate 3,100 tons of steel. Oregon's coastal bridges have suffered from prolonged exposure to marine salts, including salts in construction aggregate and salt air that corrode rebar, crack concrete, and weaken structural integrity. This process is blamed for the loss of Waldport's Alsea Bay Bridge, which was replaced in 1991. Oregon's Department of Transportation addresses rebar corrosion with cathodic protection, using an enclosure with controlled atmospheric conditions, sandblasting to remove damaged concrete and clean corroded rebar, repairs to make the rebar continuous, new concrete, a special zinc coating, and an electrical current intended to draw corrosive salts away from the rebar. The Cape Creek Bridge near Florence was the first bridge in Oregon to undergo cathodic protection, Yaquina Bay Bridge was the second, Depoe Bay's bridge was the third, and forty-one other coastal bridges have also been identified as likely candidates for the process.