Bridges are something that most drivers take for granted. They enable some really impressive shortcuts. Yet the nation's bridge population is old and in need of maintenance. Even now important bridges are closed. The Bay Bridge in Oakland, a 73 year old piece of critical infrastructure is closed to traffic. The Lake Champlain Bridge is also shut.
Given the very high levels of federal and state government debt and the poor condition of the country's bridges I think we will be seeing more and more closures in the years ahead. A cash strapped state or local government might find it does not have the budget to make repairs. Bridges could be shut for extended periods.
Try to become aware of the bridges along your commonly driven routes. They don't have to be bay crossing monsters. Even a small bridge over a dry ravine can be critical in a route. Having an awareness of the infrastructure that lets you drive carefree where you want will help you cope if that infrastructure fails. Also if you find yourself planning a move, you might want to include a study of bridge layout when evaluating your options. Living in a city or region that is heavily dependent on bridges could prove to be a mobility limiting headache over the next decade or so.