NHTS data from 2001 and 2009 shows a major increase in sustainable transportation. Image via Mobilizing the Region.

Between 2001 and 2009, the share of trips that Americans made in cars dropped by more than four percent, with walking, bicycling and transit use picking up the slack, according to new data from the U.S. Department of Transportation.

Last year, 11.9 percent of all trips were on foot or by bike, while 4.2 percent of trips were on transit. Both figures signify major increases.

The National Household Travel Survey, the source of the new stats, is the gold-standard for transportation data. As Mobilizing the Region reported, while the Census only tracks how people get to work, the NHTS gathers data on all trips taken. It also distinguishes between, say, driving to a park-and-ride bus area and walking to the local bus stop.

The downside to the NHTS is how infrequently the survey is conducted, which makes it difficult to determine how much the 2009 data reflects a larger trend, and how much may be due to temporary changes brought on by fluctuating gas prices and the recession.

The high quality of NHTS data means that it can supplement NYC DOT’s own numbers, which have shown a large rise in cycling over the same period. We’ve put in a request to the state DOT and the New York Metropolitan Transportation Council to get access to city-level data once it becomes available.