Census reports steady growth in local transit use, walking

More Seattle residents taking transit to work (data: American Community Survey)

US Census data released on Thursday confirmed more Seattle residents are taking transit to work. More are walking too. Bike commute rates remain low, however.

Even though the Census' American Community Survey sample is a large and sophisticated process, sample variation is inevitable and there are occasional anomalies at local geographies. So it's more productive to step back and look at trends than focus on shifts in one mode in one year. (I've assembled some tables with local statistics here).

In 2010, 18% of workers living in Seattle took transit to work. Last year, this had grown to 23%. It's a sharp contrast to other major cities where ridership is trending down.

Transit has gained share in nearby suburban cities too, up from 6.8% to 9.5% over eight years in King County outside of Seattle. But there's no growth in the transit share among Snohomish County residents, where it stays stubbornly stuck at about 5.9%. Pierce County grew ridership a little from an even lower base; 4.3% in 2018 vs 3.2% in 2010.

The other extraordinary success story in Seattle is far more people walking to work. More than 12% walked to work last year vs just 8.5% in 2010. Outside of Seattle, fewer have the opportunity to walk to their workplace and the walk share of commutes is low and generally falling. Seattle's walking infrastructure isn't all that much better than in 2010, so this mode shift perhaps has more to do with the shifting distribution of employment.

Walking to work has become steadily more popular, but cycling has not grown (data: American Community Survey)

Oddly, the increased number of workers walking isn't accompanied by any increase in numbers biking. At least, last year's low number turns out to have been an anomaly. Whether that was a statistical fluke (the decline from earlier years was statistically significant) or an indicator of temporary weather and construction impacts, it doesn't appear to reflect any long term trend. Even though bike counters on corridors with better infrastructure are showing growth, it isn't evident in city-level data. Bike trips may be shifting from corridors without bike lanes to those with new lanes. In any case, greater bike use in some places isn't translating to a significant shift among commuters at the city aggregated level.

Seattle's land use mean that the city is very different from the suburbs. With 37% of workers who live in King County, the city is home to 83% of those who bike to work, 78% of walk to work, and 58% of those who take transit.

There was less visible change in the mix of mode shares in other counties in the Metro area. One consistent trend, however, was the increase in the percentage of workers who work from their homes. The rate increased from 4.4% to 6.5% in Snohomish this decade, and from 3.5% to 5.7% in Pierce. There were smaller increases in Seattle. The increased time many spend in long commutes may mean some workers deciding not to commute at all.

The American Community Survey is conducted monthly, minimizing weather impacts to the annually reported data. Respondents were asked for the mode they primarily used to travel to work last week. Where a journey involves multiple modes, the survey asks for the mode used for the longest distance. The survey does not ask about non-work trips. The survey is large, covering about 2% of US households each year.