The Problem with Downtown Shuttles

A common misconception about downtown areas is that great things can be achieved by “shuttles” or “circulators,” short routes that just run around in downtown.  The problem with these lines is that they save time for the customer only if they are very, very frequent.  This is an issue that separates people who need only a symbolic service (such as a line on the map or a photo of the transit vehicle in front of the development they’re trying to sell) from people who want actual mobility.  [2015 update: I’d no longer use the term “mobility” here. I’d use “abundant access.”]

Frequency is really important, but it’s also really expensive.  Doubling the frequency of a service (i.e. halving the “headway” or elapsed time between consecutive trips on the line) comes very close to doubling its operating cost.  If you double your peak frequency (i.e. the highest frequency you run) it also doubles your fleet, which doubles your fleet capital cost, your ongoing mainteance cost, and the size that your storage and maintenance facility needs to be.  So it’s not surprising that we see a lot of downtown shuttle services that offer a line on a map, a photographable vehicle, and even some mobility for people who aren’t in a hurry, but that don’t really compete with walking.

For an example, let me pick on a very credible-looking route from a proposed downtown Oakland (California) streetcar network, from the interesting Bay Area blog 21st Century Urban Solutions, by Daniel Jacobson of Stanford.  Daniel has lots of good ideas, and I recommend his blog, so I hope he won’t mind me using his idea as an example.

Oak streetcar Orange Line
The blue, red, and green lines on this map flow across the downtown and out into surrounding neighborhoods, so they would presumably be useful to people who are travelling 2-3 miles or more.
But the orange line is just a simple square loop.  (If you know Oakland, the four streets are Broadway, 17th, Madison, and 8th.  That suggests a one-way loop, which is a topic for another time.  For now let’s pretend the loop is two-way.)
Oak streetcar orange line only
The long sides of the loop are about 770m and the short sides are about 710m, so the longest distance served by the route (from one corner to the diagonally opposite corner) is only 1.48 km or 0.9 miles.  So if you walk at 3 mph, a walk between opposite corners of the loop would take 0.3 hours or 18 minutes.
If a streetcar or shuttle bus doing the orange line wanted to be faster than walking, how frequent would it have to be?
Let’s generously assume our service averages 10 mph.  Well, the travel time onboard to go 0.9 miles at 10 mph is 0.09 hours or 5.4 minutes.  So if you just missed one trip, and the streetcar is still going to be faster than walking, that means the next one needs to come soon enough that your travel time plus wait time doesn’t exceed the 18 minutes it would take you to just walk the whole way.  The in-vehicle travel time is 5.4 minutes, so that means the headway (time between consecutive trips on the line) can be no longer than 12.6 minutes (18-5.4).
To get to that, I’ve assumed that the only market the streetcar is serving is between its opposite corners, the longest possible trip that this route can serve.   But the average trip served by this route is obviously shorter.  If you assume a shorter trip, the frequency needs to be even higher.  Let’s say we’re just travelling the length of one long side, say from 8th to 17th on Broadway.  Now the walk takes 10 minutes while the ride would take 3 min, so it’s faster to walk unless the next vehicle comes in 7 minutes or less!
If every urbanist and architect and downtown booster had been stepped through that calculation, we’d see a lot fewer short downtown shuttle services, and the few we had would be much more frequent.  Such services may be helpful for people who don’t want to walk for reasons other than time (such as weather, frailty, disability, or laziness) but they offer very little to the average person who really needs to get somewhere and whose time is valuable.
Sensitivity to frequency is also the main reason why spines of very frequent bus service, converging from routes all over the city, are better than dedicated shuttles at serving short intra-downtown trips. Downtown boosters want specialized downtown services.  But if you just want to get somewhere fast in a major downtown, head for a street where lots of bus lines are running on top of each other to provide a very high combined frequency; many downtowns have one or two corridors where a bus is coming every minute or two all day.  The key here is that the bus service is there anyway, it’s already paid for, and it’s extremely frequent. By contrast, a city will need to come up with every dollar to run its specialised shuttle, and is therefore likely to settle for a frequency like 12 min or 15 min.  That sounds good, but it doesn’t compete with walking for the short trips that the shuttle claims to serve.

24 Responses to The Problem with Downtown Shuttles

  1. Cascadian July 14, 2009 at 2:36 pm #

    Thanks for doing the math. One implication of these numbers is that the bigger the circulator, the more likely it is to be a time-saver.
    For example, assume a 2-mile diagonal. That’s a 40-minute walk. The bus route will take about 11 minutes, meaning that the circulator makes sense with headways as long as 29 minutes. A shorter route still might need a headway under 15 minutes, but still much less frequent than with the shorter circulator.
    That’s not to say that short segments on longer routes aren’t still the better option for in-city trips, but it does mean that transit planners actually have to do the calculations before declaring a circulator a bad investment.

  2. Michael Druker July 14, 2009 at 2:58 pm #

    Though I definitely agree with you about short trips needing high frequency, I’m actually not sure whether servicing short trips even makes sense as a primary goal of a transit line. Do circulators ever make sense?

  3. Jarrett at July 14, 2009 at 3:21 pm #

    In my career I've dealt with plenty of downtown business groups who'd convinced themselves that the solution to their 1-2 mile long transportation need is some kind of shuttle or circulator — streetcar or bus.  While most successful urban streetcars are longer, I think they too get oversold as short-distance mobility options.  So yes, the confusion is widespread.  Forward a link to your friends in the worlds of urban design and downtown boosterism.

  4. Cap'n Transit July 14, 2009 at 7:53 pm #

    So that’s why I never wind up using those things! I’ve been to many places that claimed to have one, and they always looked like a good idea on the map.
    Somehow, though, they never happened to be around when I needed them, so I always gave up and walked – or else took the through transit route that happened to be going where I wanted to go.

  5. Alon Levy July 14, 2009 at 8:07 pm #

    Circulators can be useful if they facilitate transfers between transportation systems. For example, take the 42nd Street Shuttle in Manhattan, which is 800 meters long and which most people use in order to get from the subway lines at one end to the lines at the other end.

  6. Cap'n Transit July 14, 2009 at 9:13 pm #

    I’d be interested to see the numbers on that, Alon. As a regular rider of the #7 train, I see a lot of people who use it to get from the Seventh Avenue trains to the Lexington Avenue trains. A lot of the Shuttle riders may be transferring from the Broadway trains to the Lex, but my hunch is that many of them are connecting to Metro-North.
    Regardless, I think you’re right that they’re transferring; I don’t know of anyone who takes only the Shuttle to get from one above-ground destination to another.

  7. Cap'n Transit July 14, 2009 at 9:15 pm #

    And that raises the question of how effective the proposed 42nd or 34th Street streetcar circulators would be. I guess it all depends on how frequent they are.

  8. anonymouse July 14, 2009 at 11:07 pm #

    Well, that you can gauge by the popularity of the crosstown buses they’re replacing. And I’d say they’re pretty darn popular, even for short trips. It seems like half the bus get off at many of the stops. But there’s another factor: what if you can’t walk at full speed? For example, if you’re elderly, or disabled, or tired, or carrying a 19 inch CRT monitor? Then the equation comes out differently and shorter trips make more sense, and you start being able to, say, transport heavy things without having to rent a car. Mind you, this market is even smaller than normal people walking, but parts of Manhattan have enough density to sustain a transit route on old ladies alone.

  9. Nathanael July 15, 2009 at 2:05 am #

    Really, really, really, really good point.
    I will say that in terms of practicality of operation, the “spine” with buses branching out all over is severely problematic, because delays in the outlying areas cascade into delays in the spine. This means that you do not get the headways you want in the spine.
    This means that a high-frequency service may need to be operated separately from the long-distance service, or at least supplementarily, as a matter of schedule reliability. If you completely separate it, you end up with the problem of “three-seat rides”.
    This can theoretically happen with segregated-from-cars rail, too, but it only seems to actually happen in very complicated (national network overlays, for instance) or very old and deterioriating rail systems.
    The only sort of “really short distance” circulators which seem to be highly effective are “shuttle from the train station/airport to my attraction” operations, which aren’t circulators at all; they’re shuttles which either run continuously (airports) or meet each arriving and departing train. These, for obvious reasons, are usually funded directly by the attraction operators.
    This leads to an obvious point about shuttles: they’re not going to replace walking unless they’re very frequent — or they show up right when you need them. Having a shuttle linked to the arrival and departure times of scheduled trains, therefore, will work for the people showing up on those trains. You can also pull off shuttles for sports events, arriving for the start time and leaving after the finish time.

  10. Aaron M. Renn July 15, 2009 at 6:39 am #

    Another great post. Again, I think a lot of people who propose these types of systems don’t ride them and/or don’t view themselves as the target riders. They see what the believe to be a problem – spread out destinations – and land on an intuitively plausible answer in a circulator. Especially since so many places have implemented them.
    I actually like the circulator as a concept, but the implementation has to be right.

  11. Multimodal Man July 15, 2009 at 6:54 am #

    Excellent post. The other argument I like to raise in addition to the service having no utility since it only can be useful for very short trips is the question I pose to people: Should we really be designing service so people don’t have to walk a few blocks? That is, since walking is the second most energy efficient mode to the bicycle (in BTUs per person mile) should we do something that most effectively is performed by the pedestrian? (The most energy efficient electric railway in the US in terms of BTUs per passenger mile is the NY subway system. The SFO trolleys and DC Metro are on par. Walking is something like twice as efficient as the NY subway.)
    Which makes me think that there are *a few* transit planners who envision transit as needing to fill a space-age role where we move effortlessly through cities on moving sidewalks, PRT pods and Segways.

  12. Jarrett at July 15, 2009 at 9:24 am #

    Thanks, Nath
    Actually, I disagree about reliability on bus spines being worse than circulators. Delay can happen for many reasons anywhere along any line. If you have a really frequent spine (every 2-3 minutes or better) made of buses coming from many routes, all converging on a common segment, one of those routes can be late but the others will still show up, yielding a minor gap between services but not really a major wait for the passenger. By contrast, if you’re relying on a single circulator line, a delay event may shut down the whole service — especially if it’s a streetcar, as streetcars are much more vulnerable to total disruption than buses are.

  13. Jarrett at July 15, 2009 at 9:35 am #

    Interesting point. My experience is that some of the affluent people who form downtown-booster theory do imagine themselves riding the vehicle, and that this is why they refuse to care about the bus service that’s already there.
    But they haven’t thought as much about what it will be like to wait for the vehicle.

  14. John Schumann July 15, 2009 at 10:34 am #

    Long-ish headways (12-13 mins) are a limited-budget-induced drawback of Portland’s streetcar line, overcome at least partly by a Next Bus sign at each station to show when the next two cars will show up. Thus, a passenger can decide if the wait will be short enough to make it worthwhile, or will be so long as to to make wait + streetcar ride longer in time than just walking. It would be more convenient to have more frequent service; but even so, the 4-mile line carries 12,000-13,000 rides/weekday, which is a pretty respectable 3,000 boardings per mile of line. Among circulators, the champ for frequency must be Denver’s 16th Street shuttle – always a bus in sight.

  15. 21st Century Urban Solutions July 15, 2009 at 12:17 pm #

    Just to elaborate on my concept a little bit,
    currently a lot of Downtown Oakland is just outside of a comfortable everyday walking range (under 8-10 minutes), so you don’t see people walking from Jack London Square to Downtown or Uptown to Chinatown very often. So many bus lines travel down Broadway at sporadic frequencies that it is nearly impossible to get from Point A to Point B downtown without extensive planning and a little luck, and one of the backbones of Oakland’s transit system, the 51, is so incredibly unreliable that there could be three bunched buses in a row or none could come for 25 minutes. Some sort of circulator is a must.
    The idea behind the Orange Line was to tie Downtown together in conjunction with the three other lines. The whole loop of the Orange Line would take about 10 minutes, so I assumed 10 minute frequencies. The main goals of the Orange Line was to connect Lakeside (upper right), Lake Merritt Bart (lower left), and Chinatown (lower right) so that no trip would really take less than 7-8 mins. Together with the Red and Green Lines (4 minute crosstown headways) and the Blue Line (8 minute headways south of 11th st.–not including regular and rapid buses–and 4 minutes north of 11th st.) you could get pretty much anywhere Downtown in under 12 minutes (including travel time and wait time).

  16. Wad July 15, 2009 at 2:06 pm #

    Strange how we have gotten this far and not brought up the“ target=”_blank”>DASH system in downtown Los Angeles, the archetype for downtown circulators.
    You’ll notice in the link that there are dozens of DASH lines outside of downtown. reflecting a more neighborhood orientation.
    The downtown DASH enabled the neighborhood routes to “sprout”.
    DASH is a service of the city of Los Angeles, not Metro. They are different government agencies.
    DASH succeeds because it flies in the face of what this article talks about. It’s not “human transit.”
    The high concept of DASH is to oversaturate bus service (run every 5 minutes) so downtown workers don’t drive during their lunch breaks.
    LADOT is at its heart a traffic engineering agency. It doesn’t run “mass transit” but only believes buses to be “harm reduction” in order to displace car trips. All of its services are either suburban express buses (with just a pitiful few reverse-commute bus lines) or DASH services.
    DASH’s premise is “transit for people who hate transit.” The downtown circulator began with Metro’s predecessor agency, but LADOT took it over in the mid-1980s and expanded it to cover most of downtown.
    In the mid-1980s, L.A. was still all buses. If people were using transit to get to downtown, they would be using peak-hour express buses, not local services. Everyone else, though, drove.
    If they did drive, traffic engineers could put up with the morning and afternoon rush hours as a necessary evil. They did not want to put up with the “third rush hour,” the time on or near the noon lunch. Their solution? DASH.
    Routes are still very much oriented around large employment clusters and popular places to eat.
    As rail was reintroduced, this added a new dynamic as the DASH buses now saw traffic going to light rail and subway stations, so the routes were modified to connect with them.

  17. Jarrett at July 15, 2009 at 9:01 pm #

    Wad. If I’d done a longer version of this article, I would have pointed to LA’s Downtown DASH for its extreme frequency, because that’s what makes DASH useful rather than symbolic (as many of the non-downtown DASHes are). You seem to disapprove of DASH and I’m not sure why; I certainly don’t. You may want to generalize about its target market, but in fact all kinds of people find it useful.

  18. Jarrett at July 15, 2009 at 9:03 pm #

    Yes, but my point is that to serve trips just out of comfortable walking range, you have to run really extreme frequency. Your orange loop would have to run both ways, every 5 minutes or so, to be reliably faster than walking.
    I do think several of the frequent bus spines within downtown are capable of being made useful for intra-downtown circulation, if AC and the city both wanted that outcome.

  19. Jarrett at July 15, 2009 at 9:23 pm #

    But in Seattle, for example, it does imply that if you don’t see the proposed First Avenue streetcar coming, walk over to Third, because buses are coming there all the time. That’s the kind of tradeoff that the streetcar will need frequency to overcome.

  20. Alon Levy July 15, 2009 at 9:48 pm #

    The proposed crosstown circulators could help, because the implementation would make them faster. Getting them from disabled snail speeds to human speeds would do a lot to increase ridership and promote more crosstown mobility. They’d provide even more mobility if they included routes further uptown, say on 96th and 125th, but you can’t always get what you want…

  21. Wad July 16, 2009 at 3:49 am #

    Don’t get me wrong, Jarrett. I like DASH, the downtown system the most.
    I am more frustrated by LADOT’s organizational mentality. I know the bus route planner, and I’ve shared with him my frustrations. The city council is not eager to redraw LADOT’s boxes, so he can’t get the kind of system LADOT needs to be.
    The lunch-hour shuttle comment is not snark. That was why the downtown service started. The original concept was RTD’s. LADOT had never operated transit until 1985, when Los Angeles built up a sufficient well of local sales tax funds to pay for bus service.
    LADOT took over some low-productivity RTD express lines as well as the subscription bus services, and made the latter open to all. It then took over the RTD Miniride service, and gave it a new name, the Downtown Area Short Hop, or DASH.
    DASH covered the Financial District well, and as expected, its heaviest ridership was around the lunch hour. Riders then pressed LADOT for better coverage to remote parking lots in downtown outside the expensive Financial District garages. This bumped up ridership in the rush hours. The addition of Metro Rail helped perk up the late A.M. and early P.M. period between the rush hours and lunch time.
    Now, downtown saw an influx of tens of thousands of residents. They are now demanding night service, even pressing for a 24-hour bus (Metro has about two dozen owl service routes).
    Another separate effort is focused on bringing back a streetcar. This is a private endeavor with no public agency studying it.
    These things sort of take a life of their own, but LADOT’s culture is one that says, “Yeah, those are some good ideas you have, but how many car trips will it displace?”

  22. Allan December 24, 2009 at 1:28 pm #

    In Portland on the Streetcar… some stores have signs inside that say when the next trolley is coming, so that the time at the stop is reduced to like 2 minutes. This solves a good chunk of the time, for the cost of an LED strip

  23. cph December 31, 2009 at 9:04 am #

    Oakland (CA) had downtown circulators (special buses) from time to time. Never seemed to gain enough ridership to make them worth keeping, though….

  24. Matt February 15, 2017 at 4:12 am #

    Keeping up 3mph walking pace while crossing busy intersections seems a bit optimistic. Also, where I’m from (Sydney), pedestrian congestion combined with aforementioned waiting at intersections often means that effective walking pace is closer to 3-3.5kph.