Bike commuters travel down along a street Thursday, May 12, 2011, in Portland, Ore. With a gallon of gas topping $4 in many parts of the country, there are signs that Americans are cutting back on ... more 
Bike commuters travel down along a street Thursday, May 12, 2011, in Portland, Ore. With a gallon of gas topping $4 in many parts of the country, there are signs that Americans are cutting back on driving. less 
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Associated Press | Photo By Rick Bowmer
Thu, May 12, 2011 1:40 PM EDT