So far this spring, I have offset 18.51 pounds of carbon dioxide, Washington, D.C.'s Capital Bikeshare tells me, the byproduct of some 30 miles I've ridden mostly back and forth between my apartment and the nearest Metro stop, which is precisely 0.58 miles away. This metric is clearly intended to convert the abstract idea of alternative transportation into a concrete environmental impact, but the number itself is a little silly. I haven't really offset much of anything. If I weren't on a CaBi bike, I'd have taken nearly every one of these trips on foot.
This is a useful way to think about bike-share's impact in any city: In its absence, what would all these one-way cyclists be doing? Does bike-share take cars off the road or commuters out of train cars? How does an entire bike-share system overlay onto a city's existing transportation matrix, and does it change not only how people travel, but where they go?
Capital Bikeshare this week released its latest mammoth member survey alongside a health survey conducted by graduate students at George Washington University. The two surveys confirm that the vast majority of regular riders (annual and monthly members) are taking trips of under 2 miles that would make little sense in a car in congested D.C.
But the member survey also directly asked users the question: What would you have done on your most recent trip if bike-share weren't available? The answer: only 4 percent of riders would have been in a personal car.
The survey also asked members how much they had increased or decreased their use of other modes of transportation since joining bike-share. The more frequently people used the system, the more likely they were to have cut back their Metrorail use (47 percent of people who made one or two bike-share trips the previous month said they had reduced their Metrorail travel; that percentage goes up to 69 percent for people making six to 10 trips, and 72 percent for people making more than 11 trips a month).
If you're one of the people who rides the crowded Metrorail system in Washington, you may appreciate the extra leg room. But some critics of bike-share will inevitably point out that this also means the system siphons fare receipts from public transit. Respondents said, on average, that they were saving $15.39 a week thanks to bike-share, and undoubtedly much of this comes from transit. But the entire picture illustrated by CaBi's latest survey is a little more complicated than a zero-sum tradeoff between buses and trains on the one hand, and bikes on the other.
More than half of the survey's respondents also said they had made at least one trip the previous month (the survey was conducted in November) that either began or ended at a Metrorail station. This means that for a lot of people – myself included – bike-share serves as a kind of extension of the public transit network, pushing its reach into neighborhoods where buses and trains don't go (or where it takes forever to walk). When we think about bike-share as a part of public transit, then it seems less like a competitor to buses and trains and more like a complement to them.
This is probably a better way of framing the goals of a bike-share system anyway, and one that will certainly apply next week as New York finally rolls out its Citi Bike system: Maybe bike-share won't take thousands of cars off the road, or save a ton of carbon dioxide. But can it extend the reach of where people can travel without getting in a car? Can it make your geographic circle larger, encompassing more businesses and potential employers and grocery stores?
CaBi's survey noted one other interesting finding about that alternative scenario where bike-share didn't exist at all. For some people, they wouldn't catch a bus, or walk, or take a taxi to go where they were already going. They'd simply stay home. Forty percent of the people surveyed used bike-share in the previous month to take a trip they wouldn't have taken otherwise, because lots of bars and restaurants and retail outlets exist at that nether-distance where it's too far to walk and nowhere near a transit stop.
That $15.39 a week in transportation savings? Maybe these people are now spending it all on beer.
Top image: DDOTDC/Flickr