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Where are people riding CaBi?

MV Jantzen has created another one of his interactive visualization tools, this time for Capital Bikeshare's public trip data. The tool lets you see where people ride to and from a particular station:

The tool looks at the trips in the third quarter of 2012. Click on any station to see what other stations people ride to and from, as lines of varying thickness. Click on any line to see how many trips there were between that pair of stations, and how "unbalanced" the trips are (whether the number of trips in one direction is close to that in the other, or if one direction dominates).

This isn't Jantzen's first interactive tool. He made one earlier this year for Metro ridership patterns. Around the same time, graduate student Rahul Nair made a tool for CaBi that has a lot in common with Jantzen's new one.

What do you notice with the tool?

David Alpert is the founder of Greater Greater Washington and its board president. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He now lives with his wife and two children in Dupont Circle. 


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It's neat when you look at something like this and realize that you were responsible for nearly every trip between two stations.

by Adam L on Jan 8, 2013 12:38 pm • linkreport

Also, why do so many people take CaBi all of two blocks? Station balancing vigilantes, perhaps?

by Adam L on Jan 8, 2013 12:42 pm • linkreport

For those two block trips, one thing this visualization doesn't include is the length or times of the trips. Those trips could be people that check out a bike from station A, ride the bike somewhere and back again and either find station A full and need to return to station B, or just find station B more convenient for them. Just speculation though.

by Another Josh on Jan 8, 2013 12:48 pm • linkreport

@Adam L

Where do you see a lot of two-block rides?

I like this tool but it has some issues with auto-zoom. I pick a station and it zooms fine, but if you then zoom in and try to look around it zips around the map, because of the auto-popup at the destination stations if you roll over one of the connecting lines.

by MLD on Jan 8, 2013 12:50 pm • linkreport


From the NH Ave and T St station, there are a surprising high number of trips between that station at the one right down the street at 17th and Corcoran, at 14th and U, and Florida and 20th. Another Josh may be right that people are going on joy riders, but I would expect such a thing for trips down along the Mall, not really in neighborhoods.

by Adam L on Jan 8, 2013 1:04 pm • linkreport

The tool definitely has some bugs with the navigation.

It seems to show that bikeshare is largely being used by those who would otherwise walk to their destination as opposed to those who would otherwise be driving. If looking at the Dupont Circle station, the two most traveled stations to/from there are New Hampshire/T & 15th/P, both of which are only a 10 minute walk.

I'm sure bikeshare does do a bit of getting people out of cars and onto bicycles, but it seems to be better at getting people off their feet and onto a bike in the street.

by UrbanEngineer on Jan 8, 2013 1:21 pm • linkreport

One problem I see with these types of analyses is that they don't take into account people using the 30 free minutes, checking in bikes, then quickly reloaning a bike and continuing rides. I know if I'm going to ride somewhere that may take over 30 minutes, or if I'm being paranoid about fees, I'll check in the bike once during a ride from, say, downtown, to RFK. This map would show two rides, each shorter than mine.

If possible, the data analyzer should look at bikes checked out by the same user from the same station within 2-3 minutes, then combine the trips.

by jyindc on Jan 8, 2013 1:28 pm • linkreport

The capital bikeshare on the southside of the Lincoln memorial appears to have not been used during the entire three months...

by Nick D on Jan 8, 2013 1:28 pm • linkreport

The data is incomplete, considering that trips that I've taken several times a week do not show up.

by Jasper on Jan 8, 2013 1:38 pm • linkreport

@jyindc: The underlying data does not have user information so there's no way to parse out the trip chaining.

@Nick D: The Lincoln Memorial and 35th/Potomac (Arlington) stations were installed in October 2012. Data only goes through September 2012.

As for removing car trips, I think making last mile connections to transit is the important part and doesn't show up in point-to-point data. For example, the trip between AU and Tenleytown metro on the surface replaces walking (or shuttle bus). But what if a person, instead of driving from their home to AU, takes the metro to Tenleytown and bikes to AU. That's a car trip removed that doesn't show up here.

by Corey H. on Jan 8, 2013 1:40 pm • linkreport

@Adam L

Agreed, both about the neatness of seeing some of the station pairs that I've apparently been propping up, and about the really short trips between some stations.

I agree that some short trips are probably joy rides (like those between the two stations at Farragut), but the 3000-odd trips between 17th/Corcoran and its near-neighbors can't all be joy rides. It seems like, at least for some trips, CaBi is less about solving the Last Mile Problem, and more about solving the Last 2/10 of a Mile Problem.

Those short trips are kinda frustrating, actually. The station at 17/Corcoran, for instance, is usually dockblocked when I need it, so it's a little disappointing to learn that I often have to walk home from 15&P because my home dock is blocked by bikes that rode all the way from 15&P. I always secretly hoped that they were all from Outer Georgetown or Far Ballston.... That said, I can't really complain that I have to walk an extra 5-10 minutes because someone else didn't want to walk 5-10 minutes, and the really short trips are probably still less than half of the total number of trips out of that station.

by Steven Harrell on Jan 8, 2013 1:43 pm • linkreport

People seem to be using the system as a replacement for the Metro (mostly rail it seems) or for more direct routes that would be too circuitous using Metro (both rail and bus). A ton of trips are made between Dupont Circle & U Street; Dupont Circle & Columbia Heights; Dupont Circle & Adams Morgan; Dupont Circle & Foggy Bottom; Union Station & Penn Quarter; Anacostia & Eastern Market; and so forth. These are trips that would require line transfers or relatively out-of-the-way trips on Metrobuses or Circulators. Perhaps this data could be used to inform WMATA about the demand for new routes.

In Crystal City and Arlington I noted that people are only occasionally using the system for interstate/intercity travel (between DC & Arlington, between Crystal City & Arlington or Crystal City & DC) but mostly for travel within the same general area. An exception exists at Rosslyn where a lot of people seem to travel to and from DC via the Key Bridge and Arlington Memorial Bridge.

In Alexandria, a lot of people are using the system to travel between the Metro and Old Town. Relatively few are using it to travel within Old Town.

by Scoot on Jan 8, 2013 1:45 pm • linkreport

@Corey H.

Agree completely with your last point. If people are using the system to complete the last (half?) mile of their journey, that's a good thing.

by Adam L on Jan 8, 2013 1:55 pm • linkreport

@ Scoot: Relatively few are using it to travel within Old Town.

Keep in mind that in the third quarter of last year, the Alexandria stations were very new. Usage needs to settle in. Also, there is still a (10-15 min biking) gap between the northern Alexandria stations and the Crystal City stations.

And the bike routes between the two are pretty much limited to the Mt Vernon trail and Potomac Ave, the latter being a mixed bunch.

by Jasper on Jan 8, 2013 1:55 pm • linkreport

I've been known to take my share of two-block trips, mainly Eastern Market to Eastern Market Metro. Saves five minutes.

by Zach on Jan 8, 2013 1:58 pm • linkreport

"imbalance" is a nice synonym for "unbalancedness" ...

by Jack Love on Jan 8, 2013 2:08 pm • linkreport


The tool has a threshold for how often a trip has to be taken to be included:
"For each station you select, the most-common route is drawn with an arrow 10-pixels thick. Segments to other stations that are less than 10 percent of that value are not included in the map."

by MLD on Jan 8, 2013 2:13 pm • linkreport

Can the dropdown of stations be grouped by muni? Also anything on "1st St" should not be sandwiched between 19th and 20th. Nitpicking here...

Sometimes the lines are hard to see.

Oh wait, maybe the stations *are* grouped by muni?

I'm not seeing popups; may be a browser issue (Chrome).


by Jack Love on Jan 8, 2013 2:13 pm • linkreport

@Another Josh: correct; there is no visualization of a trip's duration.

@MLD: I turned off the infowindow's autopan, so the view should be a bit more stable, though now you have to manually pan if the infowindow is out of view. I think this is an improvement.

@UrbanEngineer: interesting analysis! You might be right that CaBi trips are more likely to take the place of walking trips rather than driving trips. But another option is that CaBi trips are taking the place of regular bike trips, for folks who don't want to bother with locking up their own bike, or if they plan another mode for the following leg of their journey. (See for a fun tool for comparing transportation modes.)

@jyindc: The CaBi data doesn't show the IDs of the people using the system, so we can't do the analysis you propose.

And thanks @Corey H for pointing out the data is only from 2012's 3rd quarter (the latest that's been posted to Also note the arrows of course do not reflect trips that begin and end at the same station. I also didn't bother showing arrows that are less than 10% the width of the biggest arrow for that station (the biggest arrow is always 10 pixels thick).

by MV Jantzen on Jan 8, 2013 2:19 pm • linkreport

Ok I got a little farther on the popo-ups...

They appear only when you hover over a line - which makes sense - but some of the lines for the very thin trips are very narrow, and a precise hover is difficult. And sometimes the popup is half off the screen, esp. if the other station is not in the window.

Why does the map resume to a default zoom when you click a station?

by Jack Love on Jan 8, 2013 2:27 pm • linkreport

They appear only when you hover over a line - which makes sense - but some of the lines for the very thin trips are very narrow, and a precise hover is difficult.

Indeed. Would it be possible to make the same pop-up appear when you hover your cursor over the station icon in question, rather than just the line?

by Alex B. on Jan 8, 2013 2:29 pm • linkreport

I like the "Unbalancedness from" view, though it seem to only show this as an absolute value, so an inbalance of bikes coming into the the station appears the same as the same imbalance of bikes leaving the station.

One other thing that threw me for a bit was how the line width changes based on the station you are looking at. I started at the station closest to me (M St and New Jersey SE) and see that most trips appear to be between there and Union Station, which is a heavy line. However, I look at trips involving Union station, and this line becomes much lighter. I understand why this was done, it's just a bit confusing.

by Another Josh on Jan 8, 2013 2:30 pm • linkreport

RE: What are CaBi trips replacing?

Capital Bikeshare did a member survey in 2011.

They asked how you would have taken your most recent bikeshare trip if bikeshare was not an option (page 32/42pdf).
45% - Bus or Metro Rail
31% - Walk
7% - Personal Vehicle
6% - Personal Bike
6% - Taxi
2% - Other
4% - Would not take trip

So it is mostly replacing transit trips and walking trips.

by MLD on Jan 8, 2013 2:31 pm • linkreport

Short hops on CaBi are free, right? Under 20 mins?

I suppose it would be possible to short-hop your way across the whole city, no?

by Jack Love on Jan 8, 2013 2:32 pm • linkreport

@ Jack Love:I suppose it would be possible to short-hop your way across the whole city, no?

I do. I get from Georgetown to King St for "free" via a bike check in Crystal City. I can get from Georgetown to Glebe&Potomac in 28 mins. It's actually brilliant because it forces to keep biking fast. Then from there to King St is just a short ride.

It replaces a metro ride from Rosslyn to King St (or further).

by Jasper on Jan 8, 2013 3:07 pm • linkreport

@Jack Love, trips under 30 minutes are free, and the clock resets when you return a bicycle, so it is possible to short-hop across the city for free.

In fact, this past fall a bunch of my friends and I did something that I dubbed the Tour de Capital Bikeshare -- an short-hop bicycle tour of the city hitting each ward once and only once. (Our route was Waterfront-Good Hope Road-RFK-Gallaudet-U Street-Petworth-Cleveland Park-Dupont Circle.) I'll probably organize another one in the spring, swapping out Cleveland Park for Woodley Park, since the ride up Quebec on a CaBi three-speed proved more of a challenge than most people really wanted at that point in the ride.

by cminus on Jan 8, 2013 3:15 pm • linkreport

I think it's important to remember that CaBi not only replaces other modes of transportation for certain trips, but it also facilitates trips that never would have happened without CaBi.

I know in my case, I'm more likely to travel 6-10 blocks to meet a friend for lunch (for example) than I would without CaBi. A walk of that distance is too far to make round-trip during a lunch hour; Metro headways are too long midday; parking is a headache if you drive; cabs are expensive and unpredictable.

I'm a subway commuter who lives outside the Beltway, and CaBi means I do a lot more shopping and dining in DC and Arlington, because it's easier to get around. This is an under-appreciated benefit for the jurisdictions that participate in bikesharing.

by c5karl on Jan 8, 2013 3:16 pm • linkreport

Like @Jasper, I've found that Glebe and Potomac station to be a valuable waystation for connecting Alexandria to the rest of the system. I use it as a key connector when going to Old Town from central DC, typically also restarting the clock with a check-in at the Thomas Jefferson Memorial so I don't have to hurry.

by cminus on Jan 8, 2013 3:25 pm • linkreport

@ cminus:restarting the clock with a check-in at the Thomas Jefferson Memorial so I don't have to hurry.

That should give you just enough extra minutes not to have to race like an idiot ;-)

BTW: I have checked bikes quite often on more random trips around town. CaBi is really a cool way to check out town.

A month ago I used Brussels' Villo system for exactly that same purpose. It was great. I've been in Brussels many times, but biking it gave a very different view of the place. I chased down a bunch of comic walls.

by Jasper on Jan 8, 2013 3:47 pm • linkreport

Why the dearth of stations in Ward 5? It's great there's a station at the Brookland metro but that doesn't help Brookland residents' mobility until there are spoke stations connecting to hubs like the metro stop.

by Josh on Jan 8, 2013 4:19 pm • linkreport

@ Josh, the next wave of stations (which DDOT will be installing shortly after Inauguration) includes 6 (or perhaps 7, as I'm not sure of the SW boundary of the ward) in Ward 5.,-76.993539&spn=0.009418,0.026071

As to the hub and spokes comment, it appears that in many of the areas without a high station density, DC (and Arlington) has attempted to build (and subsequently broaden) corridors, rather than select hubs and surround them with spokes.

I think there are tradeoffs between the two methods, but I can see some of the positives of the corridor approach, especially as further expansions that are slightly off the corridors are within range of several nearby stations. (For example, Trinidad has not been well-served until this round of expansion, but the planned station at Neal and Trinidad will instantly provide easy access to a wide range of H Street destinations).

by Jacques on Jan 8, 2013 5:28 pm • linkreport

"Keep in mind that in the third quarter of last year, the Alexandria stations were very new. "

And to add to this, not even there the entire quarter. They only went live just before Labor Day weekend, and had their official launch a couple weeks later.

by Kolohe on Jan 8, 2013 9:19 pm • linkreport

"why do so many people take CaBi all of two blocks?"


by David C on Jan 8, 2013 11:29 pm • linkreport

@Jack Love: the drop-down is a bit unwieldy for such a long list, but it is in fact sorted by region; DC, Arlington and Alexandria (followed by the clusters). Within groups it's alphabetical, with no effort to fix numerical-order weirdnes, sorry. And I coined "unbalancedness" rather than use "imbalance" only because it felt more CaBi-speak-ish. The zoom level for when you click a station is whatever is needed to view all the arrows.

And anyone who finds IE or Chrome compatibility issues, please contact me directly.

@Alex B.: thanks for the suggestion! Try it now; you should see the infowindow when you hover over a station. In fact, you can use that trick to get stats for stations even if there wasn't enough traffic to warrant an arrow.

@Another Josh: as you noted, the busiest arrow is always drawn 10 pixels thick. There is such a difference between the busiest stations and the less-busy I think I had to do it this way.

And if anyone wants to try an undocumented feature, if you know the station IDs you can show custom clusters by plopping station IDs into the URL, like:,31015,31016,31027
(4 Rosslyn stations),31502,31504
(3 Brookland stations)

Or use the keyboard shortcuts ACDEFGHMNOUVW to see the built-in cluster groups. Though now I realize the infowindow refers to stats for only one of the stations in the cluster, oops.

by MV Jantzen on Jan 9, 2013 2:26 am • linkreport

When I click on Minnesota and Pennsylvania I see a red line to Eastern Market. When I click on Eastern Market there is no red line to Minnesota and Pennsylvania. While selecting Eastern Market, however, I do see the traffic between the two stations when I mouse over Minnesota and Pennsylvania. Just no red lines.

Not a complete visualization.

by Tom on Jan 9, 2013 9:05 am • linkreport


I posted about how the visualization works above:
"For each station you select, the most-common route is drawn with an arrow 10-pixels thick. Segments to other stations that are less than 10 percent of that value are not included in the map."

So MN/PA to Eastern Market has more than 10% of the traffic of the highest traffic route from MN/PA to another station. But in the reverse direction, Eastern Market to MN/PA does not have 10% of the traffic of the highest traffic route from Eastern market to another station.

by MLD on Jan 9, 2013 9:10 am • linkreport

Despite the my previous comment about the tool, I think it is fantastic.

One thing I noticed for the dozen stations that I selected, is that the imbalances roll downhill. I'm thinking that some sort of electric assist could solve some of the topographical balance issues.

One other suggestion for the tool is to show the imbalance as a positive or negative number based on whether the interaction between two stations produces a gain or loss of bikes.

Of course this wouldn't address the intraday imbalances that occur because of commuting patterns.

by Tom on Jan 9, 2013 9:16 am • linkreport

I've noticed distinct differences in patterns between AM and PM and that would be nice to sort on the map.

I use CaBi to ditch off metro to avoid the GODAWFUL transfer at Gallery Place in my Greenbelt-Dupont commute. I suppose you could say my Metro-CaBi transit pattern is good for Metro- it reduces overcrowding at high volume transfer stations and probably doesn't contribute to huge decreases in revenue since Metro makes most of its money on people like me who enter in the suburbs and exit in DC. That pattern for me doesn't change with CaBi usage. In fact, who knows, it may be worth Metro's effort to increase CaBi riders using my pattern to improve overall quality of transfer and customer service satisfaction around high volume transfer stations. CaBi has definitely IMPROVED my experience and relationship w/Metro--I am a happier rider now with only one line, no transfers. I know I certainly don't rag on the metro as much as I used to. The only bummer is bike availability in the AM which is why I am so psyched for more bikes at U Street.

by mehrenreich on Jan 9, 2013 10:23 am • linkreport

Adam L,

I used to work near 14th & W, so I think I have an answer to your NH Ave and T St station 2 block question. There is a Starbucks there at 16th/U/NH, and it is a much quieter, arguably nicer Starbucks than the others in the area. When I worked there, I had a choice of a longish 2 block walk to the 13th & U starbucks, or grab a bike at 14th & W and take a 1/2 block walk to the nicer Starbucks. I think the CaBi + walk route was about 4 minutes faster in terms of pure arrival time. I wonder if someone could plot the 2-block ride patterns against popular coffee shops or lunch food venues. I bet that would help to explain the result.

by Will on Jan 9, 2013 11:04 am • linkreport

Coffee shops? Lunch places?

It's just people going where they need to go. Of course people will grab a bike if they are walking that way anyway, it's faster and I have the damn key just sitting in my pocket!

Not sure why this is a mystery.

by MLD on Jan 9, 2013 11:41 am • linkreport

I agree with MLD-- if there's a two-block CaBi trip in the middle of a 4 or 5 block walk, you're shaving minutes off the trip by taking advantage of it. And that time saved can be used in any number of ways, useful or not.

by Jacques on Jan 9, 2013 4:59 pm • linkreport

Oh yeah, I didn't notice that David C also pointed out the obvious:


People will do things that save them time, especially when those things are free, like a CaBi trip.

by MLD on Jan 9, 2013 5:07 pm • linkreport

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