This afternoon, the National Capital Region Transportation Planning Board presented a new study of commuting patterns in the D.C. area. The findings quantify what we can all see around us: The share of people commuting by cars is dropping, while transit use and biking are skyrocketing.

Here are a few of the numbers for the region overall (D.C., Arlington, Alexandria, Montgomery, Prince George’s, Fairfax, Prince William, Loudoun, Frederick, and Charles):

• Driving alone to work has declined, from 67.2 percent of commuters in 2000 to 65.8 percent in 2011.
• Carpooling has declined from 13 percent to 9.7 percent.
• Transit has increased from 11.8 percent to 15.4 percent.
• Walking has nudged up from 3.1 percent to 3.2 percent.
• Biking has increased from 0.3 percent to 0.7 percent (though the TPB warns that figures under 1 percent are imprecise).
• Working at home has increased from 3.7 percent to 4.7 percent.

And among people working in the District:

• Driving alone has decreased from 39 percent to 33 percent.
• Carpooling has declined from 10.5 percent to 6.3 percent.
• Transit has increased from 32.3 percent to 40.2 percent.
• Walking has declined from 11.9 percent to 11.5 percent.
• Biking has more than doubled, from 1.4 percent to 3.5 percent.
• Working at home has increased from 3.9 percent to 4.9 percent.

The spikes in transit and biking are striking, but the figure that really jumped out at me was this one: “About 90% of the workers added to the District’s labor force between 2000 and 2011 both lived and worked in DC.”

This is extraordinary. As Office of Planning Director Harriet Tregoning pointed out at the presentation, “Our regular number is that 30 percent of people who work in the District live in the District.”

We keep hearing over and over and over again that the reason for D.C.’s recent economic success is bloated federal spending. But the 90 percent figure presents a different theory. Since the advent of home rule, D.C. has been hamstrung by its inability to levy a commuter tax, meaning that the majority of D.C.’s workers aren’t paying D.C. taxes. Now, that tide seems to be turning. For one reason or another, people who work in D.C. now want to live in D.C.—-and that means more tax revenue (and retail business, and housing demand, etc.) for the city.

You can assign credit as you will—-to the dropping crime rate, to the efforts of city leaders, to better noncar transit options in the city, or to the traffic jams on the Beltway that make commutes unbearable—-but the numbers show that D.C.’s become a more attractive place to live, and we as a city are reaping both the costs (in higher rents) and the benefits.

Graph from the TPB presentation