Commuters in the Washington region have been shifting -- slowly -- away from driving alone as their primary method of getting to and from work, according to the latest data available from the U.S. Census Bureau, which was analyzed recently by the Transportation Planning Board.
In its analysis, the TPB found that all jurisdictions added workers to their resident populations between 2000 and 2011. For example, during this time, the District of Columbia added approximately 46,000 new workers, 90% of whom both live and work in the District.
The share of commute trips made by people driving single-occupancy vehicles in the Washington region declined slightly between 2000 and 2011, from 67.2% of trips to 65.8%. The percentage of commutes by carpool also decreased during this time from 13% to 9.7%, with the biggest decreases coming from commutes originating in Prince George's and Fairfax Counties to destinations in DC and Arlington.
At the same time, the share of trips made primarily by public transit -- Metrorail, commuter rail, and local and express bus service -- increased markedly, from 11.8% to 15.4%.
Declining shares of solo driving occurred in almost every major jurisdiction in the region, but the biggest drops came in the District of Columbia, Montgomery County, Prince George's County, and Arlington County. In the District, the share of solo driving dropped from 39% to 33%.
In most other jurisdictions, the share held steady or fell just 1 to 3 percentage points and was generally between 70% and 80% of all trips.
The latest Census data which was collected for the American Community Survey, an ongoing statistical survey that samples a small percentage of the population each year, suggest that the shift away from solo driving and carpooling was mostly toward transit. The District, Arlington, and Prince George's County all saw gains of 7 percentage points or more in the transit mode share between 2000 and 2011. Charles County saw the next highest gain, moving from just 2.1% of trips in 2000 to 8% in 2011.
Federal workers had the largest increase in transit use from 2000 to 2011. The number of Federal workers that commuted by transit increased from 19% in 2000 to 28% in 2011. The $240 transit subsidy per month offered to 80% of Federal workers in the region is a likely contributor to this shift.
Biking also became a more popular travel mode over the last ten years. Regionally, 0.7% of commute trips in 2011 were by bicycle, up from 0.3% in 2000. This growth reflects about 11,000 new bicycle commute trips. The District saw the largest increase in bicycle share regionally, with only 1.4% of commuters biking to work in 2000 and 3.5% biking to work in 2011. The share of trips made on foot -- about 3% -- remained steady.
The trends suggest that the region's investment in options like transit, bicycling, and walking are paying off, and that increasing roadway congestion is making other alternatives look more attractive.
In light of changes like these, planners looking ahead to the future must think about how the region's transportation system can and should respond to changes in demand for various modes of travel.
If the share of commuters choosing transit as their primary travel mode continues to increase, for example, that will mean significantly more demand on an already crowded system. Even if the transit share were to hold steady, the region's transit system would still see close to 250,000 additional trips each day at peak periods by 2040, according to the TPB's latest forecasts of future travel patterns.
And although the share of commuters choosing to drive alone to work each day is expected to decrease, the TPB still anticipates some 450,000 additional trips by solo drivers during peak hours by 2040.
The shifts in commuting patterns revealed in the Transportation Planning Board's analysis of the latest data from the U.S. Census Bureau are a welcome sign for planners and decision-makers seeking to provide travelers with more options, especially options that do not require access to an automobile. At the same time, these shifts in commuting patterns are also a sign of future trends that the transportation system must be ready to handle.