Wireless sensor to monitor structural integrity of bridges

Wireless sensor to monitor structural integrity of bridges: "According to a 2009 estimate by the U.S. Society of Civil Engineers, more than one in four U.S. bridges are either structurally deficient or functionally obsolete. While newer 'smart' bridges have embedded wired networks of sensors to monitor their structural integrity, the high cost of installing such systems on existing bridges is simply unaffordable for strained city, state and federal budgets."