Humber Bridge single-span suspension bridge for 16 years from its opening in July 1981, until the opening of the Great Belt Bridge in June 1997, and was relegated to third place with the opening of the Akashi Kaikyō Bridge in April 1998. It is now the eighth longest single-span suspension bridge. The central span, at 1410 m (4640 ft), is the UK's longest. It remains the longest single-span suspension bridge in the world that one can cross on foot or by bicycle. The bridge is crossed twice during the annual Humber Bridge half marathon. In July 2013, work began on introducing a
Underspanned suspension bridge heavy cross-braces. The only remaining underspanned Suspension bridge in the United States is the Kellams Bridge crossing the upper Delaware River between New York and Pennsylvania. Underspanned suspension bridge An underspanned suspension bridge (also upper deck suspension bridge) is a rare type of suspension bridge that was developed in the early 19th century. It differs from its ancestor, the simple suspension bridge, in that the deck is raised on posts above the main cables. The raised deck is less stable than a deck laid on or hung below the cables, and very few underspanned suspension bridges have been built. Examples