Humber Bridge July 1981. With a centre span of and a total length of , the Humber Bridge was the longest single-span suspension bridge in the world for 17 years, until Japan's Akashi Kaikyō Bridge opened on 5 April 1998. The road-distance between Hull and Grimsby was reduced by nearly as a consequence of the bridge. The bridge's surface takes the form of a dual carriageway with a lower-level foot and cyclepath on both sides. There is a permanent speed limit on the full length of the bridge. Each tower consists of a pair of hollow vertical concrete columns, each tall and
Niagara Falls Suspension Bridge was further stiffened by guy-wires which ran from its upper deck to the top of its towers. Criticism of suspension bridges was growing after the Wheeling Suspension Bridge collapsed under strong winds in 1854. To address these concerns, Roebling added more guy-wires to secure the lower deck to the shores below. Roebling's efforts ensured that his Suspension Bridge remained standing while other suspension bridges across the Niagara River collapsed because of strong winds. Although he was not the first engineer to appreciate the need for a suspension bridge to be sufficiently rigid or to implement the methods to do so,