For the vast majority of DC’s new residents, Car Free Day (September 22) isn’t a once-a-year event, but a year-round occasion. Between 2010 and 2012, the number of car-free households in in the District of Columbia grew by 12,612 — fully 88% of new households citywide.

Graph by the author with data from the US Census.

During that time, the number of car-free households in DC has grown by 14.3%, increasing their share of all households from 35% to 37.9%. By contrast, the District only added 1,662 car-owning households since 2010, an increase of just 1.0%.

The percentage of households with one, two, and three or more cars all declined. This is even though typical DC households have considerably more money with which they could buy cars: median incomes grew by 9.3% over the same time period.

More specifically, the Census Bureau’s American Community Survey (using one-year estimates, and accessible via factfinder2.census.gov) showed that the number of car-free households in DC increased from 88,390 to 101,002, and the total of all households went from 252,388 to 266,662.

The ACS has also picked up on other consequences of DC’s growing car-freedom, like a sharp decline since 2007 in the number of DC residents who drive to work.

This doesn’t mean that new apartment buildings’ garages are all seven-eighths empty, of course. There is considerable churn among households, especially in urban areas: fully 36.5% of DC households moved at some point between 2010 and 2012, with most of those moves taking place within DC. Some who already lived in DC and own cars moved into new buildings, and others moved from the city and took cars with them.

Some existing households bought cars, and others sold theirs. New households are created when couples or roommates split, when kids strike out on their own, or when someone new moves to town. (One set of new arrivals not contributing to the trend: students living in dorms are not considered households, as the Census defines the term.)

But the net effect of all these changes is the same: The people moving into DC, or striking out on their own here, are almost entirely car-free. They are very different from current residents in that regard: only 12% of new households own cars, compared to 62.1% of current DC households. These new households are demanding many fewer parking places, much less rush hour road space, and much less gasoline.

Parking minimums prepare for car ownership that just doesn’t exist

These statistics show why DC does not need to continue requiring costly and environmentally destructive new parking garages within new developments that accommodate the city’s growing population.

However, some longtime neighborhood activists have been fighting lower parking minimums. At this week’s hearings on zoning code changes, multiple opponents of lower parking minimums also cited Census data to argue that parking was necessary: they said that the numbers of cars per household in DC was “holding steady” at 0.9.

In fact, the number of cars per household in DC declined from 0.90 to 0.86. Maybe if you round off to one decimal place, both numbers become 0.9 — proof that nothing has changed!

These trends aren’t unique to DC; instead, they’re consistent with what other growing, dense cities are seeing. Michael Rhodes from Nelson\\Nygaard, a transportation consulting firm, recently calculated that in San Francisco, a similar 88 percent of new households are car-free. DC’s car-freedom is also consistent with national and global trends pointing towards lower urban car ownership recently and into the future. The decline in car ownership should come as little surprise given DC’s booming population of auto-averse millennials.