Francis Scott Key Bridge
By Jeremy Smith [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
License: Creative Commons Attribution-Share-Alike (CC BY-SA)
Contractors took borings of the harbor bottom in the spring of 1969. Bids for construction of the proposed tunnel were opened on July 30, 1970, but price proposals were substantially higher than the engineering estimates. Officials drafted alternative plans, including the concept of a four-lane bridge. Key Bridge with Baltimore in background, viewed from Cox Creek Industrial Park, November 2011
The bridge, at an estimated cost of $110 (USD) million, represented the best alternative because it allowed for more traffic lanes and carried lower operating and maintenance costs than a tunnel. In addition, a bridge would provide a route across the Baltimore Harbor for vehicles transporting hazardous materials (these materials are prohibited from both the Baltimore Harbor and Fort McHenry tunnels).
Construction began in 1972, and the bridge opened to traffic on March 23, 1977. Including its connecting approaches, the bridge project is 10.9 miles (17.54 km) in length. Other structures along the thruway include a 0.64-mile (1.03 km) dual-span drawbridge over Curtis Creek and two 0.74-mile (1.19 km) parallel bridge structures that carry traffic over Bear Creek, near the former Bethlehem Steel Sparrows Point plant, this portion of the project not being fully complete until the late 1990s.
Located in an area rich with American history, scholars believe the span crosses within 100 yards (91 m) of the site, marked in the water off the bridge by a stars and striped painted buoy, where Francis Scott Key witnessed the bombardment of Fort McHenry on the evening of September 12, 1814. That battle inspired Key to write the words of the Star Spangled Banner. Located just southeast of the bridge are the ruins of Fort Carroll.