Post #1168: Capital Bikeshare again, part 2

Posted on July 4, 2021


More than two years ago, I looked at Capital Bikeshare use in suburban Fairfax County and concluded that Bikeshare was largely a waste of the taxpayers’ money.   The use of those docked rental bikes was far below what is seen in (e.g.) central D.C., and as a result, the average cost per trip was exceptionally high.  My estimate was that Tysons area Capital Bikeshare trips had an average cost of about $25 each, and an average length of less than a mile.

In this post, I refresh that analysis and see whether or not use of those bikes has changed markedly in the subsequent two years.

To cut to the chase, it appears that the only truly successful Bikeshare stations in this area are the three stations serving Merrifield.  (Successful in the sense of getting a lot of use).  As the Town of Vienna contemplates where to put their its own racks, there may be some lesson there. Or maybe the Vienna racks these will end up just as nearly-useless as they appear to be in Tyson’s, just up the road.

You should look at the just-prior post to see all the links to my original analysis of this issue.


The map above is my rendering of the Capital Bikeshare stations in Fairfax County, including the City of Falls Church.  A station is a place with one or more bicycle racks where a bicycle trip may originate or end.

I’ve placed them into four “clusters”, from top to bottom:

  • Reston
  • Tysons
  • Falls Church
  • Merrifield

Data source:  Detailed summaries of all bike trips taken on Capital Bikeshare bicycles can be downloaded starting form this URL:    .  There is no file for April 2020.  Starting May 2020, the entire format of the underlying data files changes, so that everything from May 2020 onward is in a completely different format.  They removed information allowing individual bikes to be identified, for reasons that I can’t fathom.  The removed their estimate of trip duration, but they added the latitude and longitude of the bike stations (something that has to be merged onto the earlier files).  You would also need to get to their Github data repository to find (e.g.) the file showing latitude, longitude, and name of each station for use with the pre-May-2020 data.

On the map, these clusters of Bikeshare stations appear to be isolated from one another, and that is in fact true.  Below (Table 1), you can see the origin-destination pairs for all Capital Bikeshare trip legs from 2017 to the most recent data available.

Definition of “a trip”.  Throughout this, bear in mind that a “trip” is most properly termed a trip leg.  If you take a bike from one rack to another in the morning, that’s a trip.  If you take it back to the original rack in the evening, that’s a trip.  If you take a bike out, ride it around, and return it to the same rack, that’s a trip.  So a trip just means everything that happens between the time you take a bike out of a rack, and you return it to a rack.

The point is, if six people use these bikes to commute from Metro to work in the AM, and from work back to Metro in the PM, that’s a total of twelve trips.

For example, 98% of Bikeshare trips that started in Reston ended in Reston.

Aside:  If you don’t understand why there are two tables above, you are not alone.  The first table groups all the trips by where they started, and shows you where they ended.  By contrast, the second table groups all the trips by where they ended, and shows you where they started.  If someone biked from Reston to Tysons, that trip would be counted in the top line of the first part of the table, and on the second line in the second part of the table.  That’s probably still not clear, but it’s as clear as I can make it, and it hardly matters for this analysis anyway.

The only apparent exception to this strong separate across these four regions is Falls Church.  But that’s only an apparent exception.  Those stations are directly adjacent to the rest of the Capital Bikeshare system.  There are a lot of trips that cross the boundary of that cluster, but they are, by and large, just short trips to nearby bike racks.  As is shown in the table below.

The Bikeshare system is (or at least, was) oriented toward trips of half an hour or less.  The half-hour point is where trips begin incurring additional charges.  And that matches the observed trip distance and duration pretty well.  A typical (median) trip is around a mile in length, and takes well under half an hour.

Capital Bikeshare is also largely oriented toward annual memberships.  As you can see, about two-thirds of trips are for members, except for the Merrifield area, where members and casual users are split about 50/50.  (I believe that casual users are anything other than annual memberships, and so include per-trip payment by credit card or purchase of day or mult-day passes).

Here’s a snapshot of system capacity and usable bicycles as of July 4, 2021.  The capacity will remain more-or-less constant, but the bike availability will depend in part on the number of bikes that were actually in transit at the time the bike rack reported in to Capital Bikeshare.  (The numbers in the three left columns may not sum to total bike docks because some of those bike docks maybe out-of-commission).


Use rate for Capital Bikeshare bikes

This section shows how many trips (trip legs) were taken in each area, from 2017 to May 2021.  This is really where the rubber meets the road, in the sense of demonstrating the exceptionally low use of these rental bikes in this area.

Two things make this analysis difficult.  First is the pandemic.  Use of all modes of transportation declined in that period, particularly public transportation and work-related transportation.  Second is the fact that some of these bike stations are new, and those tend to show increased rates of use over time.

For now, I’m ignoring both and just presenting the data as-is.

Here’s a graph of average daily trips, by month, for the four Fairfax Bikeshare regions.

Use is obviously seasonal, with lows in winter and highs in mid-summer.

It’s fairly clear that Reston is now a mature market.  Peak bicycle use was essentially constant for the three years leading up to the pandemic.  If the typical user is a commuter (two trips a day), then during the peak months, the entire Reston Bikeshare network serves about 18 people on a given day.

Tysons saw an increase in use in 2019, from perhaps 12 trips per day in peak months in the prior years, to almost 20 trips per day in 2019.  That appears to be due almost entirely to an expansion of the number of stations in that area.  Prior to 2019 there were 10 stations, and during 2019 that expanded to 15.  That 50% increase in the number of stations matches the 50% increase in the number of trips.

That said, my entire critique about the value of these rental bicycles in Vienna centered around the cost of running that Tyson’s network, compared to the use it saw.  And that really does not appear to have changed.  Roughly speaking, Capital Bikeshare increased their investment there by about 50%, and the number of daily trips increased by about 50%.  Without (yet) going through the formal arithmetic again, it’s a good guess that they’ve gone from six users on a typical peak-month day to ten users, and that each of those bike trips still has an average cost of around $25 per trip.  As with Reston, the entire investment in that equipment benefits perhaps ten people a day during the peak months.

My guess is, if we’re lucky, that’s what use is going to look like in the Town of Vienna.  If you live here, it’s far more convenient to use your own bike.  For one thing, you can park it wherever you want, and are not restricted to driving it only from one Bikeshare rack to another.  For another, nobody is crazy enough to buy themselves a 50-lb three-speed fat-tired bike.

The only market this is likely to serve in Vienna is individuals who want to bike from the Tysons’ metro area to Vienna and back.  Even then, that’s more than the distance for a typical Capital Bikeshare trip in this region.  We might also get some visitors from Vienna Metro, but it would be quite a task to get that heavy bike from low-lying Vienna metro to the center of town.

At this point, I’ve run out of steam.  I think I’ve made my point.  Despite all the happy talk in recent news coverage of this, these Bikeshare bikes remain woefully underused out here in the suburbs.  I may revisit this to look more closely at Merrifield, but I don’t think that’s the model for what’s likely to happen in Vienna.  In all likelihood, we’ll get racks and bikes, but no riders, all paid for by your I-66 tolls and other taxpayer-financed sources.