"""FILE - This April 30, 2012 file photo shows a """"road closed"""" construction sign in Springfield, Ill. Here are a few items that have been largely missing in the presidential campaign: planes, trains, roads and bridges. Most of the nation's transportation network was built in the last century, and in some places dates back to the 1800s. Our aging highways, bridges, trains and buses are frequently in need of repair or replacement, and no longer can handle peak traffic demands. More than 140,000 bridges are structurally deficient or obsolete. And the problem will only worsen as the nation's population grows. (AP Photo/Seth Perlman, File)"""
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