America’s bridges are aging. Almost four in 10 – 39% – are 50 years or older, and an additional 15% are between the ages of 40 and 49.  Most of the country’s bridges were designed for a lifespan of 50 years, so an increasing number of bridges will soon need major rehabilitation or retirement.  It’s estimated that local, state, and federal governments need $123 billion for bridge maintenance, rehabilitation, and replacement in the coming decade.