Study Shows Hope for Seattle Bike Infrastructure

By Josh Cohen September 30, 2010

The U.S. Census Bureau released the results of its American Community Survey on Tuesday. The survey polls about 3 million households nationwide, gathering information such as demographics, economic stats, and, most interestingly for my purposes, how people commute to work.

The numbers don't show a bicycling revolution between 2008 and 2009.  Nationally, the percentage of people who ride to work held steady at 0.55 percent and most major cities either held steady or saw about a one percent increase. The ACS reports Seattle ridership remained essentially stagnant  at 2.99 percent (versus 2.94 percent in 2008).

Though it would be exciting to see a jump in the number of bicyclists from 2008 to 2009, it makes sense that that didn't happen. Stick with me through some serious nerding out to see why there's great hope for Seattle.

Rutgers University planning professor Dr. John Pucher is one of the leading bike transportation researchers in the US. A significant portion of his research centers on what spurs increases in the number of people who ride bicycles. His findings are fairly common sense: The more bicycling infrastructure a city has (i.e. the safer bicycling seems to be), the more bicyclists there will be. Conversely, the more bicyclists there are, the safer bicycling becomes.

In his 2009 report "Infrastructure, Programs, and Policies to Increase Bicycling: An international review", Pucher says there's a "positive and statistically significant relationship between bike lanes and levels of bicycling." He also reports that a study of more than 40 cities "found that each additional mile of bike lane per square mile was associated with an increase of approximately one percentage point in the share of workers regularly commuting by bicycle."

Perhaps more importantly, the study examines the effect of different types of bike infrastructure on ridership. Traditional bike lanes and sharrows had some positive effect on perception of safety and ridership, but more innovative infrastructure---such as colored lanes, dedicated bicycle signals, bike boxes, and cycle tracks---had far greater impact.

So, that brings us back to the stagnant ACS numbers. Until recently, and with only a handful of exceptions, Seattle's on-road bicycle infrastructure has been dominated by traditional bike lanes and sharrows (with an emphasis on sharrows). As Pucher's report shows, that sort of infrastructure doesn't inspire the feelings of safety and comfort needed to get your less-confident bicyclists out on the road.

However, the Seattle Department of Transportation has lately taken a strong turn toward innovation. They've been experimenting with far more buffered bike lanes (such as the ones on 7th Ave, N 130th Street, and along E. Marginal Way) and parking-protected bike lanes (such as the ones proposed for Linden Ave. N. and Admiral Way SW). Yesterday, SDOT installed the city's very first bike box, on Capitol Hill. This is the type of infrastructure Pucher says is needed to increase ridership.

In essence, Seattle is just starting to experiment with the kind of protected bike infrastructure that Pucher's research says has helped bicycling grow in the world's best bicycling cities. The impact of that infrastructure obviously isn't shown in the latest ACS study and may very well not show up for a while (though I'm really looking forward to seeing SDOT's fall bike count numbers). But it's a safe bet that if SDOT continues to experiment with the sort of quality protected infrastructure that helps bicyclists feel safe, Seattle's ridership will grow and grow.
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