Complete streets would mitigate traffic congestion and improve air quality. The potential to reduce carbon emissions by shifting trips to lower-carbon modes is undeniable. The 2001 National Household Transportation Survey found 50 percent of all trips in metropolitan areas are three miles or less and 28 percent of all metropolitan trips are one mile or less – distances easy to walk, bike, or hop a bus or train. Yet 65 percent of the shortest trips are now made by automobile, in part because of incomplete streets that make it dangerous or unpleasant for other modes of travel. Complete streets would help convert many of these short automobile trips to multi-modal travel. Simply increasing bicycling from 1 percent to 1.5 percent of all trips in the U.S. would save 462 million gallons of gasoline each year.