Millennium Bridge, London people walking caused small sideways oscillations in the bridge, which in turn caused people on the bridge to sway in step, increasing the amplitude of the bridge oscillations and continually reinforcing the effect. On the day of opening, the bridge was crossed by 90,000 people, with up to 2,000 on the bridge at any one time. Resonant vibrational modes due to vertical loads (such as trains, traffic, pedestrians) and wind loads are well understood in bridge design. In the case of the Millennium Bridge, because the lateral motion caused the pedestrians loading the bridge to directly participate with the bridge,
Albert Bridge, London light and thus to reduce the risks of ships colliding with the fragile structure during the day. At night, a network of 4,000 low-voltage tungsten-halogen bulbs illuminated the bridge. In 1993 the innovative use of long-life low-energy lighting was commended by Mary Archer, at the time Chairwoman of the National Energy Foundation. Except for Tower Bridge, built in 1894, Albert Bridge is the only Thames road bridge in central London never to have been replaced. Intended as a temporary measure to be removed in 1978, the concrete central piers remain in place, and although in 1974 its lifespan was estimated