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Directional rider flows on Metro

In July, I analyzed how people travel within the Metro system, using a survey to estimate riders' choice of alternate routes.

Because the data used was for average daily travel between origin and destination stations, it was not possible to determine which stations were primarily 'commute from' stations and which were primarily 'commute to' stations. However, after my July post, WMATA offered to give me time-specific data, which allows us to look at commuting patterns. The data used for this revised analysis looks at trips taking place between system opening and 9:30AM. The dataset comes from an averaging of AM Peaks from early May 2009.

Click to enlarge.

The methodology used to assign trips to each link in the system is the same used for the initial model and analysis, published in July. In the above graphic, each segment of the Metro line comprises two lines. One line represents inbound trips, the other represents outbound. The thickness of each line represents the total volume on any given segment.

From the graphic it is clear that, not surprisingly, most AM peak trips on Metro are inbound. Most of the reverse commuting in the region seems to occur on the Shady Grove branch of the Red Line, the Vienna end of the Orange Line, and the common Blue and Yellow Line segment in Arlington and Alexandria.

This analysis also gives us a good estimate of the proportion of passengers traveling on different lines at the junction points. For instance, at Rosslyn, 65% of inbound passengers entering the station do so on the Orange Line, while 35% come in on the Blue Line. Outbound trips are slightly more balanced, with 60% on the Orange Line and 40% on the Blue Line.

King Street

In addition to measuring volume on each line segment, this analysis allows us to consider each station based on how "busy" it is. Metro's faregates keep a record of the number of entries and exits at each station, but they are unable to determine where people transfer. As a result, stations like Metro Center and L'Enfant Plaza appear less busy (on paper) because the people transferring there are not counted. Below is a list showing Metro stations ranked on their level of traffic.

Note that the "transfers" column does not count passengers who don't change platforms. This is because for someone changing to a train on the same track with multiple common stations, it is not clear where they transfer. Transfers in the table below only refer to passengers who change platforms, from the outbound Blue to the inbound Yellow at Pentagon, for instance.

Metro Station Passenger Traffic (AM Peak)
Table is sortable by clicking each field heading
Overall Rank Station Entries Exits Transfers Total
1Metro Center1,66017,38829,11748,165
2L'Enfant Plaza2,86714,40224,49841,407
3Gallery Place1,5649,94521,00732,517
4Union Station10,24013,106-23,346
5Farragut West1,21216,626-17,838
6Farragut North1,12116,630-17,750
9McPherson Sq1,60411,840-13,444
10Dupont Circle4,6218,552-13,173
11Foggy Bottom2,26810,046-12,314
12Shady Grove10,400902-11,302
13Crystal City4,2196,812-11,031
15Fort Totten3,7139845,2049,919
16Silver Spring6,4102,796-9,206
18West Falls Church6,8941,390-8,284
19Federal Triangle2108,066-8,276
20New Carrollton7,1551,046-8,201
21Pentagon City5,5922,306-7,898
22Judiciary Sq4877,230-7,717
27King Street3,0853,2041896,478
28Capitol South7905,677-6,467
30Columbia Heights4,0991,804-5,903
31Friendship Heights3,3602,194-5,554
32Branch Avenue5,243298-5,541
36Court House3,3341,599-4,932
37Navy Yard6614,195-4,856
38Southern Avenue4,314483-4,797
39Federal Center SW4754,214-4,690
42Medical Center1,1003,313-4,413
46Van Ness2,9421,290-4,232
47Largo Town Center3,552410-3,962
48Rhode Island Ave2,6521,197-3,848
49Dunn Loring3,028812-3,840
50Woodley Park2,761900-3,661
51Braddock Road2,590826-3,416
53U Street2,0261,346-3,372
54Eastern Market2,3111,059-3,371
56New York Ave1,0872,023-3,109
57Georgia Ave-Petworth2,156881-3,037
58College Park2,123873-2,996
59East Falls Church2,639256-2,895
61White Flint1,5151,335-2,850
62Prince George's Plaza2,089728-2,817
63Virginia Sq1,8171,000-2,817
64Cleveland Park2,428310-2,738
65Van Dorn Street2,437300-2,737
66Addison Road2,392329-2,720
67Potomac Ave2,148492-2,641
69Mt. Vernon Sq1,1641,106-2,270
70Naylor Road2,012248-2,260
71West Hyattsville2,045201-2,246
72Minnesota Ave1,360840-2,201
73National Airport6701,486-2,156
77Benning Road1,715283-1,998
78Forest Glen1,773143-1,916
79Eisenhower Ave7231,068-1,791
80Congress Heights1,442286-1,728
82Capitol Heights1,442286-1,728
84Morgan Blvd1,119149-1,267
86Arlington Cemetery22262-284

Looking at the 'exits' field reveals some interesting attributes. This field can be considered a reasonable proxy for office access. The first station in exits outside of downtown Washington is Arlington's Rosslyn station at #12. Medical Center is Montgomery County's leading station for exits at #21 and is followed by #22, King Street as the highest in Alexandria. Fairfax's most exited station in the AM Peak is West Falls Church at #33. Prince George's County's New Carrollton comes in at #42. In the case of West Falls Church, it is likely that many of the exits are passengers transferring to buses headed for Tysons or Reston.

Matt Johnson has lived in the Washington area since 2007. He has a Master's in Planning from the University of Maryland and a BS in Public Policy from Georgia Tech. He lives in Greenbelt. Hes a member of the American Institute of Certified Planners. He is a contract employee of the Montgomery County Department of Transportation. His views are his own and do not represent those of his employer. 


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Beautiful figure. Tufte would be proud!

by Tsar Bomba on Nov 17, 2009 12:07 pm • linkreport

Good analysis Matt. Numbers speak.

1) The Orange/blue thing in Rosslyn makes perfect sense. There are twice as many orange trains as blue trains. All of them are full, so that yields a near perfect 1:2 ratio in traffic.

2) What is surprising is that the blue line has higher ridership compared to the yellow line in Pentagon and King St.

Based on that, can anybody explain me why people want to re-direct the blue line along the yellow line? The blue line is stuffed to the max, and more so than the yellow line.

I am surprised how few people transfer at King St.

I am curious to see if the pm numbers show the complete opposite.

by Jasper on Nov 17, 2009 12:20 pm • linkreport

Interesting analysis. Do you have comparable numbers for the evening peak, or perhaps even a "lunch peak"?

by Froggie on Nov 17, 2009 12:23 pm • linkreport

One thing to remember is that the survey was unscientific, so these rider flows are to be considered estimates. In order to get a true count, somebody would need to conduct a statistically significant survey of riders.

The ratio of Orange to Blue trains at Rosslyn is roughly 3 to 2, so not quite twice as many.

The issue with rerouting the Blue Line right now is not particularly clear cut. However, once the Silver Line opens, WMATA will have little choice in the matter.

One particularly interesting phenomenon is the imbalance at the junction points. Take L'Enfant Plaza, for instance. 62% of inbound passengers come in on the Green Line, a large majority. But outbound passengers are 56% on the Yellow Line. Pentagon and King Street show similar cases, where the dominant demand is on opposite lines for the inbound and outbound tracks.

by Matt Johnson on Nov 17, 2009 12:29 pm • linkreport

Jasper: The King St transfer numbers only account for people going from Franconia to Huntington or something. People who transfer from a northbound Blue to a northbound Yellow aren't included in the counts, because we don't know if they transfer at King Street, Crystal City, Pentagon, or anywhere else along the shared segment.

by David Alpert on Nov 17, 2009 12:39 pm • linkreport

Great map Matt.

Based on my own personal experience, your hypothesis about WFC exits being mostly bus transfers is correct. I get off there every morning to bus to Reston, and nearly everyone else seems to also get on the buses to the Reston, Tysons, Herndon, AOL @ Dulles, Dulles Airport, etc. Can't imagine there's too many jobs within walking distance of WFC Metro.

by Chris Loos on Nov 17, 2009 12:57 pm • linkreport

Thanks for the confirmation. I think that says a lot about the lack of (balanced) TOD in Fairfax and Prince George's. Fairfax and Prince George's Counties only have one station each in the top half under exit volume, WFC and New Carrollton.

by Matt Johnson on Nov 17, 2009 1:03 pm • linkreport

Not too many surprises. The extent of inbound to outbound blue/orange transfer at Rosslyn is one. East/west movements within NoVa are bigger than we intuitively think. There's an argument there for better Rooute 7 transit, I think.

The number of entrances and exits at Union Station surprised me. Entrances I expected: transfers from MARC/VRE. But I didn't quite appreciate how many people work around there. An argument for the separated blue line to come through Union Station.

That there are more exits than entrances at Eisenhower Ave. is interesting. There's a destination there. An argument for cross-bridge transit (an extension of the green line from Branch Ave.) into Eisenhower East, perhaps.

by jim on Nov 17, 2009 1:13 pm • linkreport

Everytime I see Mt Vernon Sq. so low on the map, I can't help but wonder why. It's centrally located in a dense area with a highly diverse income range, and right below a convention center. Is this a 'heads should roll' situation, or can we expect its numbers to improve over time? That number is so incredibly low for a downtown station. Seems like such a waste...

by JTS on Nov 17, 2009 1:22 pm • linkreport

Mount Vernon Square really is a more residential station, when you think about it. The station's entrance is all the way up on M street.

Think about it - the front entrance of the Convention Center on the square (K St, essentially) is just as close to the Mt Vernon Sq entrance as it is to the Chinatown station entrance.

by Alex B. on Nov 17, 2009 1:28 pm • linkreport

The left side of your octopus looks terribly atrophied. What a shame.

More seriously, Tenleytown is more of a destination than you would think. Some of that must be for Homeland Security and AU, but that's still unusual.

by Neil Flanagan on Nov 17, 2009 1:29 pm • linkreport

In terms of boardings, Mount Vernon Square is comprable (and slightly better than) Shaw, so the residential side of things isn't so bad.

In terms of the "exit" statistic, though, remember that convention-goers have different travel profiles than many working people.

If conventioneers come to conferences after 9:30, they're not shown in these statistics. That may be more likely because Metro's day passes don't work until after 9:30. But really, if you compare Mt Vernon Sq to the other downtown stations, there aren't all that many offices. And since the station is so close to Gallery Place, workers coming from the Red Line might just walk from 7th/H instead of transferring.

by Matt Johnson on Nov 17, 2009 1:30 pm • linkreport

I live within walking distance of several stations including Mt Vernon Square. Unlike say, U Street, Mt Vernon is not near any major retail district and the entertainment venues near there are few and rare in number. The area S of the station has few people or businesses and due N are a lot of institutional uses (e.g., churches) that probably don't generate daily traffic. The convention center itself is something of a failure and only intermittently attracts large numbers of people. The lack of users at Mt Vernon makes the station a little uncomfortable at night. My guess is that some people, like me, who have a choice probably get off some place with more pedestrian traffic around it.

by Rich on Nov 17, 2009 1:39 pm • linkreport

@ Matt: Once the Silver line comes, it's really easy. In stead of orange-orange-blue, they run orange-silver-blue. The Silver line still coincides with the orange line for a very large part.

@ David: Ah. I didn't get that. That doesn't surprise me.

@ Jim: Eisenhower has quite some government around it. Patent Office, Federal Courthouse and Hoffman also has a big government building.

by Jasper on Nov 17, 2009 1:45 pm • linkreport

Actually it's not that simple.

I wrote about this a while back:

Anyway, if it helps, think of it this way.

Any track at a junction point can handle a train every 135 seconds.

Essentially, this means that every 12 minutes, the inbound track at Rosslyn can handle 5.3 trains. The current configuration is OR, BL, OR, OR, BL (3 Oranges, 2 Blues). This means that the Orange Line has a headway of 4 minutes during rush periods (12/3) and the Blue Line has a headway of 6 minutes (12/2).

When the Silver Line opens, there are a few things we could do for headways, none of which are particularly helpful.

SL, OR, BL, SL, OR (Silver-6mins, Orange-6mins, Blue-12mins)
SL, OR, BL, OR, BL (Silver-12mins, Orange-6mins, Blue-6mins)
SL, OR, BL, SL, BL (Silver-6mins, Orange-12mins, Blue-6mins).

Metro is picking door number 1.

by Matt Johnson on Nov 17, 2009 1:54 pm • linkreport

These numbers confirm what I had always thought about my Metro line. Silver Spring is effectively the terminus when it comes to ridership. It also has a lot more places to walk from. Silver Spring is also the bus hub for the eastern Red Line. It's also far more beltway-accessible than Glenmont.

by Cavan on Nov 17, 2009 2:03 pm • linkreport

Quick Question: I commute from Silver Spring to Suitland every day. I typically transfer at Chinatown, but occasionally at Ft. Totten if the Red line seems backed up. Where are my transfers counted?

Also, the outbound green line past L'Enfant and even more so past Navy Yard is gloriously empty. Maybe 10 people in a car, most of whom are going to the Suitland federal complex.

by Paul on Nov 17, 2009 2:15 pm • linkreport


"Metro is picking door number 1"

There are some alternatives. They could alternate 2S2O1B and 2S1O2B (door number 1.5?) to give average 8 minute headways on both orange and blue, for example. Looking at the thicknesses of the paths on C6 and K6, it's not clear that one set of riders should be favoured over the other (particularly since some of the WFC riders will move to the silver line once it opens), and, as I noted above, there's a fair amount of blue/orange interchange at Rosslyn which dropping blue to 12 minute headways would kill.

by jim on Nov 17, 2009 2:44 pm • linkreport

Wow -- my home station, Stadium-Armory, is 75 out of 86. I guess that what happens when acres and acres of mostly empty surface parking occupy all of the land on one side of the station.

by rg on Nov 17, 2009 2:49 pm • linkreport

Also, you misspelled "Bethesda" in that table.

by Neil Flanagan on Nov 17, 2009 3:05 pm • linkreport

The model is not all-or-nothing. Based on survey reponses, different trips are assigned to different links (where an option exists) based on percentages.

I don't have the model in front of me, but I believe that a trip from Silver Spring to Suitland would assign 100% of the trips on links B9-2, B8-2 and on links F1-2 through F9-2. It would assign 50% of those trips to links E6-2 through E1-2 and B7-2 through B2-2.

But it's not always that simple and it's not always 50%.

@Neil, Thanks. Bethesda has been fixed.

by Matt Johnson on Nov 17, 2009 3:17 pm • linkreport

This is awesome.

by fedward on Nov 17, 2009 4:11 pm • linkreport

@ Matt: Hmmm. I am confused. I was fairly convinced it was
so 2 oranges for every blue.
Did not know it was
so 3 oranges, 2 blues.

I still don't get why they have to think in fives. If they go to
they keep the rough ratio of two trains west, one south the same, and they even need to change the track less. Would save time, not?

I know that the orange line gets ridiculously busy, but so does the blue line. Because the frequency is lower, and because some trains a 6 car trains. It often takes to Braddock or King St until I get s seat.

Anyway, he true solution is not messing with that switch. It's building an M St line, and a street car from Rosslyn to Georgetown across Key Bridge. Or a line along Route 50 (Annapolis-Middleburg). Too bad our politicians keep thinking that toll roads are the unicorns of traffic problems.

by Jasper on Nov 17, 2009 4:54 pm • linkreport

Metro doesn't think in 12s they think in 60s. Their measurement is TPH, trains per hour. However, for the sake of creating a graphic, 12 (1/4 of 60) is an excellent divisor. And it comes out so that the train headways are correct. It's a lowest-common-denominator thing.

by Matt Johnson on Nov 17, 2009 4:58 pm • linkreport

sorry, that should have been 1/5 of 60. I type faster than I read sometimes.

by Matt Johnson on Nov 17, 2009 4:59 pm • linkreport

Very nice, clearly showing the cramming that occurs downtown. Strongly argues for some additional measures to cope with the strains on the main system, and building redundancy to counter accidents or emergencies.
e.g. the recent GGW post recommending that the trolley going down Rhode Island Avenue not get entangled into the other Metro stations.
Also, my oft-mentioned hobby horse of pedestrian tunnels linking Gallery Plc/Metro Ctr and Farragut N and W.

by SJE on Nov 17, 2009 7:32 pm • linkreport

I commute from Ballston to Pentagon City, and due to the crappy headways on the outbound Blue Line, Metro is already the slowest and least pleasant of all the ways I can commute to work (the others being the ART 42, biking the mt vernon trail, or driving). Making the headways even crappier would be annoying, but it wouldn't affect my commuting behavior any, since I already don't take Metro unless I have no other choice.

When I stay at my fiance's place in Reston, if I don't leave for work before 6am there's a significant chance that driving the 25 miles to Pentagon City will take me longer than the 2 hrs it would take me to bike it. And that makes the 13-minute blue line headways not seem so bad. Nothing makes me appreciate Metro in all its crappy, run-down glory like sitting in fairfax county gridlock.

by lilybelle on Nov 17, 2009 8:13 pm • linkreport

When are these amounts for the past week, month, season etc?

Im betting stations such as Stadium Armory, Van Ness, Pentagon City, Wheaton, Largo Town Center, Ballston change different times of the year.

Stadium Armory is almost a ghost town during the summer when Eastern High is out and the same for Van Ness when UDC is closed

Largo, Wheaton, Ballston & Pentagon City are always packed during the holiday shopping season ( day after thanksgiving, christmas eve, day after christmas etc) I have been to each on those days and they are packed with people coming from the adjacent malls/shopping centers.

by kk on Nov 17, 2009 9:17 pm • linkreport

As noted at the bottom right portion of the diagram and also in the paragraph immediately preceding the diagram, the data used in this analysis comes from averaging origins and destinations taking place during the AM Peak (opening-9:30AM) on May 5, 6, and 7, 2009.

by Matt Johnson on Nov 17, 2009 9:27 pm • linkreport

@kk - Metro likes to use May ridership numbers because they are the best for year-to-year comparisons. Winter months fluctuate due to weather. In the fall, ridership is lower in election years when Congress adjourns early. Summer is heavily affected by trends in tourism. March and April vary depending on when the cherry blossoms fall. By a process of elimination, you're left with May.

by Ben Ross on Nov 17, 2009 9:29 pm • linkreport

Would be curious to know about Green-to-Yellow transfers at Mt. Vernon Square...

by The Kleiner on Nov 17, 2009 9:35 pm • linkreport

fascinating--thanks for this! I can't believe how few people use the Waterfront station, which is the closest one to me, but I bet the Circulator has a lot to do with it. There are probably at least 100 people each morning who ride it instead of taking Metro...I'm one of them!

The Circulator might also account for some of the low traffic at Mt. Vernon Square. That's the closest metro to where I work, but frankly there just aren't a lot of businesses over there. People are either going to Howard (so the Shaw station) or downtown (so Gallery Place).

by Stacy on Nov 17, 2009 9:40 pm • linkreport

It gives a decent idea of where Metro could allow bikes in the system at rush hour without harming capacity (the way San Francisco does). The Eastern Red line to Ft. Totten. The northern green to Gallery Place and the southern green to Navy Yard. The PG County Blue and Orange to Stadium. For example.

by David C on Nov 17, 2009 10:12 pm • linkreport

David C, I wouldn't want bikes on the eastern red line during rush hour. Maybe they could work between Glenmont and Silver Spring but after everyone boards at Silver Spring and Takoma, forget it. Most seats are filled by the time the train gets to Silver Spring. The remaining few are filled by the first passengers who board at Silver Spring. It's standing room only for the reson of the Silver Spring passengers.

by Cavan on Nov 18, 2009 11:17 am • linkreport

Also, BART (you meant BART, right?) has a much lower ridership than Metro. About 1/3 as much during rush hour. It makes it easier to accomodate bikes when there's such a disparity in ridership.

by Cavan on Nov 18, 2009 11:19 am • linkreport

@ Cavan: So how come WMATA is nearly falling apart while having three times as many riders as BART? Or is that the reason why CA is bankrupt?

by Jasper on Nov 18, 2009 11:49 am • linkreport

Wow, that's a hell of a non-sequitir, Jasper.

by Alex B. on Nov 18, 2009 11:52 am • linkreport

Cavan, that's fine. I'm not out there at rush hour, I was basing my guess totally on the diagram above. So we could cut it off at Silver Spring, which connects nicely to the trail network. There is some part of the system where letting bikes on at rush hour would work fine - and the diagram gives an idea of where that is. The proportion is probably much less than it is on BART, for the reason you stated, but it does exist. Perhaps the cutoff is at 10,000 trips.

by David C on Nov 18, 2009 1:36 pm • linkreport

Were you able to record the source & destination for each passenger? It would be interesting to get a better sense of the flow of Metro-goers during their commute.

If you're able to provide me an n x n table (where n = number of stations) which corresponds to Trip Start vs. End, I'd be happy to piece together a visualization using a tool called Circos: You would probably have to model transfers in the data model as well.

by Stefan on Nov 19, 2009 7:30 am • linkreport

I also thought the numbers were interesting showing many more people on the inbound Blue line than the Yellow at Pentagon station. Probably many get off west of LEnfant Plaza and don't want to transfer? Even if it might cost them a few minutes?

How could you allow bikes on only certain segments of a line? Seems impractical.

I'm not surprised about Union Station. It would be interesting to see how many of the exits are transferring onto Amtrak versus exiting into the neighborhood for work, etc. My guess is that there are quite a few people who have Amtrak on their mind....

I was definitely surprised not to see more people transferring from inbound Orange to outbound Blue. You always get so many people getting on outbound at Rosslyn in the PM, I assumed it was at least a good number going home from their jobs in Pentagon City, etc. Maybe not?

by Josh S on Nov 19, 2009 10:30 am • linkreport

How could you allow bikes on only certain segments of a line? Seems impractical.

As I mentioned they do it on BART.

It's pretty simple. Step 1 identify sections/stations of Metro where cyclists are allowed to use Metro during rush hour. This may be different for the morning rush than the evening rush Step 2: State rules about this publicly. Step 3: Enforce rules same as you do now, but with new exceptions.

by David C on Nov 19, 2009 10:58 am • linkreport

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