The CBB is officially called the William Preston Lane, Jr., Memorial Bridge. The dual spans near Annapolis provide a direct connection between Maryland's Eastern Shore recreational and ocean regions and the metropolitan areas of Baltimore, Annapolis, and Wash D.C. With a shore-to-shore length of 4.3 miles, the bridges are among the world's longest and most scenic over-water structures. The two-lane original span was opened to traffic in 1952. The parallel structure opened in 1973 and has three lanes for westbound travelers. The original span then became a two-lane roadway for eastbound traffic. All lanes are reversible. Generally, three lanes are thrown in the direction of peak traffic. Summer weekends tend to have very heavy traffic to and from the 
Eastern Shore, and to ocean resorts such as Ocean City, Maryland, and Rehoboth Beach, Delaware. Each bridge has a suspension span over the main shipping channel. The main span has a horizontal navigational clearance of 1,500 feet, and a vertical navigational clearance of 186 feet, and the main shipping channel passes under the main span, utilized by oceangoing ships to and from the Port of Baltimore.
Eastern Shore, and to ocean resorts such as Ocean City, Maryland, and Rehoboth Beach, Delaware. Each bridge has a suspension span over the main shipping channel. The main span has a horizontal navigational clearance of 1,500 feet, and a vertical navigational clearance of 186 feet, and the main shipping channel passes under the main span, utilized by oceangoing ships to and from the Port of Baltimore. During 2001, nearly 23.9-million vehicles crossed the Bay Bridge. There is a one-way eastbound toll plaza just west of the bridge. Two axle vehicles pay $2.50.