Basics: The Spacing of Stops and Stations

The unglamorous but essential struggle over the spacing of consecutive stops or stations on a transit line is an area where there’s a huge difference in practice between North American and Australian agencies, for reasons that have never been explained to me as anything other than a difference in bureaucratic habit.  In Australia, and in most parts of Europe that I’ve observed, local-stop services generally stop every 400m (1/4 mile, 1320 feet).  Some North American agencies stop as frequently as every 100m (about 330 ft).

(Already I can hear someone asking “but how many blocks is that?”  Well, it depends on how long your city’s blocks are.  Even in San Francisco, where block length is wildly variable, I’ve heard people insist on asking for a standard in blocks, which is complete nonsense.  Living on a short block doesn’t make you more entitled to a bus stop near your house.)

San Francisco is at it again, trying to rationalize its stop spacing on some of its most frequent lines.  So I thought I’d take the occasion to lay out some stop spacing basics.

The geometry of stop spacing works like this.  Every stop or station has a walk radius, the area from which most people would be willing to walk to a stop.  In the most idealized world, which is where some planning happens, this radius defines a circle around each stop.

Slide1

How big is the walk radius?  Actually, different people are comfortable walking different distances, so a truer view of these circles would be very fuzzy, gradually dissapating further out from the stop. You don’t want to look at that, though, and it’s hard to do geometry with it, so transit planners generally observe that the walking distance that most people seem to tolerate — the one beyond which ridership falls off drastically — is about 400m (around 1/4 mi) for a local-stop service, and about 1000m (around 3/5 mi) for a very fast, frequent, and reliable rapid transit service.  (I, personally, will walk further than this.  You may not be willing to walk even this far, but as an approximation the 400m rule for local service seems to work pretty well.)

But of course, the circle is what the walk radius would be if you could walk absolutely anywhere in the area, including diagonally, through buildings, etc.  In the real world, we walk along some kind of network of streets and paths.  The design of that network is therefore a crucial element of walking distance, which means that it’s also relevant to stop spacing.  Consider these two drawings, from this post:

Cul-de-sac circles

These happen to both be in the Seattle area, but your city probably contains examples of both of these network types.  The car-oriented network on the left is full of obstacles to the pedestrian, so the actual area you can walk to (the blue network) is less than a third of the ideal radius (red).  On the other hand, in a dense grid (of streets and other pedestrian links), like the one on the right, maximizes the possible walking distance.  The actual area within walking distance is diamond shape, i.e. a square rotated 45 degrees from the transit line.  Almost two thirds of the ideal radius is in walking distance in such a network.

Note how these things are connected in chains.  Street network determines walking distance.  Walking distance determines, in part, how far apart the stops can be.  Stop spacing determines operating speed.  So yes, the nature of the local street network actually affects how fast the transit line can run!

How do we decide about spacing?    Consider the diamond-shaped catchment that’s made possible by a fine street grid.

Slide2

Ideal stop spacing is as far apart as possible for the sake of speed.  But of course people around the line have to be able to get to it. In particular, we’re watching two areas of impact:

  • The duplicate coverage area is the area that has more than one stop within walking distance.  In most situations, on flat terrain, you need to be able to walk to one stop, but not two, so duplicate coverage is a waste.   Moving stops further apart reduces the dupicate coverage area, which means that more unique poeple and areas are served by the stops.
  • The coverage gap is the area that is withing walking distance of the line but not of a stop.  As we move stops further apart, the coverage gap grows.

We would like to minimize both of these things, but in fact we have to choose between them.  Close stop spacing means smaller coverage gaps but larger duplicate coverage area.  Wide stop spacing means the opposite.

If we are doing a local-stop service, and we assume that people will walk 400m, then the diamonds are 800m wide.  If we then set the stop spacing at 400m, the diamond on the left will touch the one on the right.  In other words, every point on the line will be in a duplicate coverage area.  The coverage gap, meanwhile, gets smaller.  In fact, if the stop spacing is the same as the walking distance standard, the coverage gap’s area and the duplicate coverage area are the same.  Play with this yourself until you believe it.

So does that make this the right answer?  Not necessarily for two reasons:

  1. Which is worse, creating duplicate coverage area or leaving a coverage gap?  It depends on what you’re trying to do.  In fact, this is arguably connected to the tension between designing for ridership and designing for coverage, generally to meet social service needs.  If you care mostly about the latter, you want to minimize the coverage gap so that everyone has access, and you don’t care that much of the resulting line is slower and therefore less attractive to other riders.  On the other hand, if you want to maximize ridership, you’ll worry more about the duplicate coverage gap, because in addition to representing wasted coverage, closer stop spacing means slower operations.  Both more expensive to operate and less attractive riders; so you’ll tend to want to push stops further apart.
  2. If this is like most urban fabric, there’s more stuff (residents, jobs, activities) close to the transit line than far from it, which means that there’s more stuff in the duplicate coverage area than in the coverage gaps.  So if that’s true, then we’re facing again the eternal danger of maps: they invite us to misread pure area as though it represents the stuff that matters.  If we set the stop spacing at 400m, the duplicate coverage area is the same as the coverage gap area, but if there are more residents, jobs, and activities in the duplicate coverage area, the two aren’t really in balance.  If you valued duplicate coverage and coverage gaps equally, you’d ideally plot the actual locations of residents, jobs, and activities, and then push the stops just far enough apart so that the amount of this stuff in the duplicate coverage area was the same as that in the coverage gap.  (Though, again as per point #1, there’s no particular reason that these two things should be the same; you can strike a balance anywhere based on your goals in running the service.)

So that’s the geometric tradeoff that governs stop spacing in flat terrain with well-connected street networks. You can see how variations in terrain would shift the calculation.  If the transit line is climbing a steep hill, you can make a case for stops closer together.  Walking downhill is usually easier than walking uphill, so some people will value having two stops so that they walk downhill to one to depart, and walk downhill from the other one as they’re returning.  That’s why stop spacing is often a bit closer when going uphill or downhill.

In general, though, we always want to push stops as far apart as possible while still providing enough access, both for speed and, because the fewer stops we have, the more infrastructure we can afford to provide at each.  But the limits of our ability to widen stop spacing is defined by the geometry I’ve outlined.

Finally, while I’ve been talking about local stop service with a walk distance of about 400m, the entire calculation is exactly the same for any distance.  For example, if we are placing rapid transit stops, and we think that the maximum walk distance to them is about 1000m, we can set the stops 1000m apart; thus we end up with the duplicate coverage area that’s the same size as the coverage gap.  Then we can argue about whether, in the given situation, we should push wider or narrower.

Of course, there are all the other kinds of access: Park-and-Ride, Kiss-and-Ride, cycling, etc.  Still, the walk is the dominant factor in transit access potential, because even if you use a vehicle for access, you’re likely to be a pedestrian at the other end of your trip.  Of course many people are pedestrians at both ends.  (The exception is when you take your bicycle on board, which will always be a problem at crowded times.)  Sooner or later, we are all pedestrians.

Finally, here’s a fun question to think about:  If you had two parallel transit lines, how might the stop locations on one of them affect the logical locations of stops on the other?  What’s the furthest apart that the lines can be (in terms of multiples of the maximum walking distance) for this consideration to matter?  Think about it before you look at the comments, because someone’s probably written the answer there!

46 Responses to Basics: The Spacing of Stops and Stations

  1. M1EK November 5, 2010 at 5:06 pm #

    First the 1/4 mile rule was defined up to 1/2 mile for ‘rapid transit’ and now you’re trying to pull 3/5 mile. GMAB. The time commitment required for 1.2 miles of walk with associated waits at intersections is more than the vast majority of ANZUS choice commuters would ever consider outside possibly NYC.
    When I see this kind of defining up it’s really an admission that serving choice commuters is hard, so we have to pretend that they’re lazy.

  2. Cap'n Transit November 5, 2010 at 5:30 pm #

    The main issue I want to raise is that different pedestrians have different ranges. A transit line that serves a large number of elderly or disabled passengers should have closer spacing.
    Forget parallel lines, there is also the issue of local/express lines. Here in Queens we have the #7 train that stops every 6-7 blocks (1/3 mile), and two frequent buses that run on Queens Boulevard below. Two years ago the MTA changed the bus stops from about 1 1/2 blocks apart to roughly three blocks, and people were not happy. It didn’t help that they moved one of the stops further from the senior center.

  3. EngineerScotty November 5, 2010 at 5:36 pm #

    A few comments:
    Living on a short block doesn’t make you more entitled to a bus stop near your house.
    Living on a short block may make the time to get to the bus stop longer or more treacherous, if the shorter blocks mean more crossings to cover the same distance. This is especially true if the crossings are busy and you can expect to wait for the light to change or the traffic to clear.
    Regarding the difference between social service and ridership lines–another important issue you left out is stopping policy. Most rapid transit lines stop at every stop regardless; but many local bus routes in the US only stop when there’s a passenger waiting, or when someone on board explicitly signals the need to get off. Many “social service” lines here in Portland have very short distances between stops (<200m, and in some cases <100m), but the “effective” stop distance for a given run is much larger than that, because most stops are skipped on a given run. And indeed, when converting a social service line to a ridership line, one of the challenges frequently is stop consolidation–the short stop distances on the social service line become inappropriate for the high-ridership line.
    And many rural service, or late-night services–including on some TriMet runs–adapt an even looser stopping policy of “anywhere along the line wherever it is safe”. Some rural transit agencies I can think of will even deviate from the planned route to drop off passengers at their front door–effectively acting more like jitneys or share-taxis than like scheduled bus service.

  4. David Marcus November 5, 2010 at 8:22 pm #

    Since nobody’s yet answered Jarrett’s extra credit question, I’ll take a stab.
    The first part, where should the stops be located on the second parallel line, is easy. They should be spaced exactly between the stops on the first line, to maximize the coverage area for the second line filling in the coverage gaps from the first line.
    As to how far apart the lines can be before this stops mattering…if we take the 400m maximum walking distance with the stops ever 400m (per the Australian/European standard), then a parallel line spaced 600m from the first line would perfectly fill in the coverage area gaps. As the line gets further away, the overlap diminishes until by 800m the lines aren’t working together at all.
    The biggest learning to me from the last part is that any closer than 600m and the lines are wastefully covering the same area. That would mean crosstown buses in Manhattan are optimally spaced about 7 or 8 blocks apart.

  5. mikef0234 November 5, 2010 at 8:33 pm #

    Where buses operate on an arterial grid, the buses must stop at least at each intersecting arterial to facilitate transfers. On a half-mile (800-metre) arterial grid, typical in western North America, stops spaced at 400 metres should be located once half way between intersecting arterials and once at intersecting arterials.

  6. mikef0234 November 5, 2010 at 8:46 pm #

    Just to clarify, parallel routes should be twice the walking distance and stops on parallel routes should all be lined up with each other. Stops on perpendicular routes will fill in the remaining gaps, which would fill a social service requirement for coverage.
    I suspect the arterial-grid spacing of many cities was chosen to maximize the development potential around a minimum number of streetcar lines, resulting in the present half-mile/twice walking-distance arterial grid.

  7. Alon Levy November 5, 2010 at 8:51 pm #

    With rapid transit, the difficulty of building it means that it’s there to last, so there’s more TOD around it. This means that development clusters more around stations, allowing transit agencies to push interstations further out. That’s why you usually see rapid transit interstations substantially longer than a kilometer: among the world’s largest systems, the distances cluster around 1.2-1.3 km.
    When you have parallel lines, usually you have to put the stops on the same cross streets, instead of offset by half. The reason is that development tends to cluster along streets, so the most useful destinations tend to be on the same cross street. You get bigger coverage gaps this way, but at least the stops are right where people want to go.

  8. anonymouse November 5, 2010 at 10:36 pm #

    EngineerScotty raises an important point: walking time is not directly proportional to distance if you have to cross big streets with non-trivial wait times. And more importantly, this increases the variance of walking time, meaning you have to leave earlier, especially if the bus you’re trying to catch runs infrequently. It’s very frustrating when the bus stop is on the opposite side of a very wide street, and you’re waiting at a light that takes 3 minutes, and watch the bus come and go while you wait to cross the street. I’d postulate that there’s some relation between walking distance and standard deviation of walking time, and line frequency. And I’d also guess that there’s some “average trip speed effect”, in that people are willing to walk further to get to faster services.

  9. Jarrett November 5, 2010 at 10:53 pm #

    @all
    David Marcus’s answer is the one I was after. When you just have two parallel lines, and are not dealing with frequent intersecting services, it’s logical to put stops on one street offset with the other. This will be relevant whenever the distance between the lines is less than twice the maximum walking distance, so that the point of the diamonds on one street fit into the coverage gaps between the diamonds on the other.
    Yes, when you have frequent intersecting streets, this consideration is superseded by the need for stops at the transfer points. But there are plenty of cases where that doesn’t apply.
    Finally, to commenters who want to attack the assumptions used to construct this exercise, fine. There’s plenty of room for disagreement about walking distances, as I’ve said in the post. But when it comes to designing service we can’t serve everyone’s pleasure in this regard, so we end up selecting reasonable median values for walking distance and planning to those. And yes, as we all know, there are also plenty of variations based on the quality of the walk experience and obstacles to it.
    But I will continue to emphasize that transit does have an intrinsic geometry, and that understanding this geometry is important if we’re going to make good decisions about it. The geometry becomes visible only if you make simplifying assumptions (e.g. uniform distribution of development, flat terrain, etc). All of the posts in this “Basics” category have done that.
    In other contexts, I’ve seen important people quibble over the simplifying assumptions because the don’t like implications the underlying geometry. Beware this slippery slope of endless assumption-questioning, because as I said in the “Field Guide to Transit Quarrels,” the facts of geometry tend to prevail in the end.

  10. Alon Levy November 5, 2010 at 11:47 pm #

    Jarrett, you didn’t make those simplifying assumptions very clear. On the contrary, you posed this exercise after warning of the “eternal danger of maps” and talking about practical development distributions.

  11. M1EK November 6, 2010 at 8:20 am #

    Jarrett, I have no problem with the assumptions; but rather the defining-up over the years of ‘acceptable walking distance’ from 1/4 to 1/2 and now 3/5 of a mile. That directly contradicts actual trends in the population.

  12. Leo November 6, 2010 at 9:24 am #

    When rapid transit stops are spaced 1km apart, you need a bus in the same corridor to provide local service for spaces in-between stations.
    For example, Toronto runs a local bus parallel to the Yonge subway north of downtown, because the subway stops are not within walking distance.
    Bus stops on Toronto’s legacy bus and streetcar network tend to be 200m apart. 400m stops would be more of a BRT thing.
    When we vacationed for several weeks in Riga, Latvia, my wife found the 400m stop spacing there very surprising. It conflicted with our habit of walking to the next stop when there was nothing coming.

  13. Cap'n Transit November 6, 2010 at 11:22 am #

    I find it a bit sad that so much of this discussion comes from a point of view of scarcity. Yes it’s true that if all your routes are heavily subsidized by stingy motorists who see transit riders as lazy welfare cheats, you need to economize on stops. But not every town is Scottsdale.
    Some of us live in places where the majority of people take transit, and where we could indeed serve just about everyone’s pleasure if we weren’t wasting so much money and public space serving the pleasure of the wealthy minority who drive.
    On Fifth and Madison Avenues in Manhattan we’ve got local buses, limited-stop buses and express buses, and about 450m away there’s the subway, with parallel local and express services, and even the commuter rail line, if you want to go faster or farther. In some sections the entire curb is one long series of bus stops.
    In those cases, it is absolutely appropriate to have stops less than 200m apart to serve not just the elderly and disabled, but people who don’t want to walk further than that, for any reason or for no reason at all.
    In a soup kitchen or an institutional cafeteria, sure, you don’t have the resources to accommodate everyone’s wishes, so you make a big batch of slop and everyone gets their scoop of slop or else they go hungry. But you take a very different approach at the Four Seasons, or even at Burger King.

  14. Cap'n Transit November 6, 2010 at 12:54 pm #

    I don’t mean to suggest that there’s anything wrong with the specific assumptions that you’re making, Jarrett, but I would appreciate if you could be a bit more clear when you’re assuming something that isn’t necessarily the case elsewhere.
    I also appreciate that your post is relatively free of the moralizing tone that I often hear when transit planners discuss stop spacing. When you have an abundance of transit, you don’t have the people who want short walks fighting over the scraps with the people who want speedy trips and the bean counters who want to save on gas and wages. When the pie is small, we can at least refrain from judging people who want one or another, and just try to find an arrangement that everyone can live with.

  15. TransitPlannerMunich November 6, 2010 at 4:02 pm #

    In 2009 I attended a conference, where a presentation from researchers from the State University, Portland (Oregon) was given. Conclusion: the ideal bus stop spacing is 1200 feet, 360 meters:
    http://www.vt.bv.tum.de/extern/mobil.TUM2009/abstracts/4A%20Public%20Transport_mobil.TUM2009_abstracts.pdf
    The same team from Portland had published one year before a paper saying 930 feet – about 280 meters – as ideal spacing:
    http://www.its.pdx.edu/upload_docs/1248894217RWAeWSDYZ9.pdf
    Obviously the ideal distance keeps growing, even in the U.S. – especially when they mention that for Boston an ideal spacing of 400 meters was the result of a different study.
    I would prefer a more practical approach:
    What is your target group?
    If you aim at “captive riders”, then you could expect your “clients” to walk, walk, walk. Probably your transit system will be heavily subsidized, so why make it easy for people to board a bus. 400 meters, 500 meters – who cares? On the other hand, when your transit agency serves a city in the U.S., walking could be seen as something unamerican. Or when you are in New York you assume that people with healthy legs will walk anyways to the next subway station. Who rides a bus there is obviously seen as mobility impaired in any way (maybe even without a driver’s licence), so those people will be happy so move with pedestrian speed in a bus and a bus stop every other block or shorter will be perfect.
    If you want to offer an alternative for the car, then you should have a spacing allowing the bus to go with a more decent speed, but also to limit the walking distance. “Aus den Augen, aus dem Sinn” – what translates into “Out of sight, out of mind” is also true for transit. And no one, except some transit enthusiasts and people scared of driving, will voluntarily decide to walk much more than 5 minutes to any transit stop. To a bus stop, regardless of all BRT-enthusiasm, even shorter. The maximum walk to a bus stop is for those people usually about 300 meters, to a metro/subway stop about 500 meters. And that is not the spacing between the stations but includes the walk from the side streets. I made a calculation in the past for my professional use and the result was an ideal bus stop spacing of 400 meters between the stops. A compromise of acceptable speed and acceptable walking distance. If the distance between the stops is larger, the bus will be faster but every rider also at one point has to walk to and from the stop and loses then more time he/she needs extra for walking than he/she saved before by the faster bus ride. The same is true if the distance between the stops is shorter – you are faster at the bus stop but lose more time when riding the bus. You can easily calculate this delicate balance down to the minute for your city, taking into consideration the average lenght of a bus ride in your city. (By the way, if your buses have a headway of 20 minutes or more, forget all this, then anyways everyone with a driver’s license will ignore your lines)
    This is true even for metro/subway lines. The Munich Metro sytem has a station every 700 to 900 meters within the city limits (outside the spacing is larger). But: The trains are long and a typical platform about 120 meters – 400 feet. Including the escalators, mezzanine and stairs to both sides on a typical station for example in north-south-direction there is usually a distance of 250 meters, 800 feet, from the most northern access stairs of a station to the most southern access stairs of a station. So when you have every 800 meters a station, then the distance between the most northern stairs of the first station to the most southern stairs of the next station to the north is more likely 600 meters. The maximum walk for a person living between those metro stations to the next station entrance is 300 meters. And – psychologically for a rider the moment counts when he/she reaches the stairs, not the platform or the train. And: the long platforms and trains make it possible to have larger spacings between the stops and a higher average travel speed but still an attractive walking distance to the next station. A hidden secret of success of metro/subway systems. A secret that BRT cannot imitate. Except when Jarret comes up with some Chinese 200-meters-bus-monsters (called “people eater dragon” or so), but believe me, they only would exist in his wet dreams.
    Reality check, also for Jarrett’s bonus question:
    In my neigborhood there are two metro/subway tunnels running parallel south to north. One with a headyway of 5 minutes during peak time, the other tunnel with a train every 2.5 minutes. The distance beween those parallel metro tunnels is 1.200 meters, 4000 feet. (capacity per train over 900 passengers)
    Still there is a very high demand on a parallel running north-south tram line – situated just in the middle, 600 meters, 2000 feet away form each tunnel. For a lot of transit planners the tram would be not neccessary. Still demand is so high, that a headway of 7.5 minutes with vehicles with a capacity of 200 riders is not sufficient anymore. And in the metro tunnels the trains reach also their maximum capacity already.
    By the way, there are now also two bus lines in east-west-direction in operation, in a distance of 250 meters. Both really successful.
    Conclusion: no one likes to walk more than 200 meters to a bus stop or 300 meters to a metro access (entrance!) or a tram stop. But also no one wants to sit in a bus that stops every 100 meters. So try to make stop distances of 400 meters between bus/tram stops and 800 to 900 meters to metro/subway stops on paper. And then have fun with reality when you discover that you have enough points of interests, schools etc. or important intersections, maybe just demands from politicians so that you end up placing stops 300 meters away from each other. The fate of a transit planner. And before you get depressed, try it with priority at traffic lights to speed up your buses again.

  16. ian November 6, 2010 at 4:04 pm #

    “In general, though, we always want to push stops as far apart as possible while still providing enough access, both for speed and also because the fewer stops we have, the more infrastructure we can afford to provide at each.” Yes–while this is true for infrastructure and, in general terms for speed, the speed relationship is certainly not linear for a typical suburban bus route. Assuming a ‘hail-stop’ situation (the bus only stops where someone indicates they wish to get on or off), as the number of bus stops is increased, the numbe of stops where the bus is actually required to stop on any given trip will also increase, but at a continually slower rate. Hence the effects on overall route speed will be diminishingly small. Hence, compared with ‘conventional’ thinking, for suburban bus routes we should perhaps go for more stops rather than fewer (and keep a lot of them basic to minimise the infrastructure costs); we should not worry much about duplicate coverage area; but should more focus on minimising the coverage gaps. The problem would seem amenable to rational analysis, examing a range of real-life route situations and the trade-offs involved in having more or fewer stops. This seeems like an ideal PhD topic–but I assume someone must have already been there and done that?

  17. JJJ November 6, 2010 at 10:06 pm #

    I think picking a number like 400 meters is not a good strategy unless you’re in Manhattan. And even then, as others have mentioned above, there is enough demand that there are various overlapping services.
    It makes more sense to design stop distances on a line by line basis.
    Every other city has changes in elevation and changes in density. It’s not uncommon to have a few apartment blocks, then a ginormous school, then a car dealership, and then a busy commercial center.
    So instead of placing stops equally apart, you might have two in the apartment region, one by the front door of the school (and then nothing by the athletic fields), maybe one by the car dealership, and then 2 in the busy commercial district.
    And on top of land use and density, you need to take into account connecting lines, grade changes and cross streets.
    A rule of thumb may be more harmful than useful. Someone might say “hey, these stops are 1,300 meters apart, we need something in the middle” even if there’s nothing worth stopping for.
    So a minimum stop distance would definitely be more helpful then a maximum, but even then, you may want to make exceptions for senior centers and school and hostile pedestrian regions.
    Now, what makes too many stops a problem? Dwell time. There are better ways to speed up a line than eliminating stops:
    -Eliminating bus pull outs, so buses do not have to merge back into traffic
    -All door boarding
    -POP fare system
    -Signal priority
    -Bus lanes.
    And a transfer program that allows for local/express service on the very same lane. Nothing wrong with a bus stopping every 100 meters if you can ride the express that stops every 1,000 meters, transfer almost immediately, and get taken the next 3 blocks

  18. Alon Levy November 6, 2010 at 10:19 pm #

    The problem with flag stop operation is that it kills reliability. People need to know, with as much certainty as practical, that the bus will arrive at a specific time. If it leaves early, or if it’s late because it stopped too much, then people learn that the buses are unreliable and choose other modes of transportation.
    If the stops are basic, without shelter, then it’s even worse. All it takes is one downpour, and anyone above the poverty line will decide that it’s better to buy a car than wait an unknown number of minutes in the rain.

  19. david vartanoff November 7, 2010 at 12:23 am #

    In a study of delay factors on a major route AC Transit (Oakland et al) stop elimination was thought to save 20 to 30 seconds. Dip swipe fare media wasted far more at the busy stops. Bottom line more time can be saved by POP or at a minimum flash passes than stop elimination.
    Depending on the characteristics of the route a far more useful strategy night be a local/express mix in base day. In another AC case, where there is express service during daylight, evening locals tend to be faster than daytime expresses but often skip “express” stops as much as “local” stops because ridership is more random as most riders are homeward bound rather than heading to commercial centers.

  20. hallam.jon November 7, 2010 at 2:02 am #

    Hey,
    In answer to the question, the parallel lines should be 400m apart, such that when the stop spacing on both lines is also 400m, the covered area will be complete and without overlap. I’ll also note that whilst this abstract view is a good starting point, local issues will demand adjustment, as Jarett acknowledges.
    Approaches like this, especially for more rapid-transit-like systems, are where public bicycle hire schemes such as Paris’s Velib are so powerful, by turning that walk radius into a much larger cycle radius.
    Yours,
    hallam.jon

  21. hallam.jon November 7, 2010 at 2:11 am #

    Edit:
    Current estimates from such schemes indicate people are willing to cycle a length about three times as far as they’d walk. Since accessible area goes up by the square of linear length, this makes your rapid transit system a factor of nine more useful. Almost a whole order of magnitude improvement. The ‘extreme’ cost of these schemes – Transport for London will spend 140M over six years for about 5,000 bikes (estimated at 100,000 daily users) to be redeemed by usage fees – should therefore be compared to the build cost of the two additional parallel transit lines that would otherwise be required (the expense of which could also be redeemed by the cost of tickets).
    PS: Sorry for the double post!
    Yours,
    hallam.jon

  22. TransitPlannerMunich November 7, 2010 at 2:23 am #

    In Munich we have:
    – boarding on all doors, with 4 doors on the articulated 18-meters-buses
    – most trips made by monthly passes, POP-system
    – ticket machines inside all buses, no tickets sold or checked by the driver
    – signal priority
    – bus stops built as curb extensions, even elevated for faster and easier access
    Still I would not like to have each 100 meters a stop – even if you have express stops every 1000 meters. Most passengers will not board on the express stops and also not leave the bus on an express stop. So they need then to take a local bus first, maybe transfer then to an express, and if they are unlucky also transfer again to a local bus to reach their destination – or transfer again to a different line. What a torture. Also, in what frequency can you run express buses and local buses parallel on the same line? Most systems offer not more than a 10-minutes-fequency, for matter of costs. If you have then a local bus every 20 minutes and an express every 20 minutes you lose me as a rider already – I am only not sure if I will buy a bike or car instead.
    Also, in an urban environment inside a city usually an average trip by bus is about 2 kilometers, often less. You do not want to change between local and express on this distance.
    If you have every 100 meters a bus stop, chances are high that during peek hours there will be a rider waiting for you at each of those stops. The bus will indeed by stopping, boarding, accelerating again lose about 25 seconds, no matter how smart the system is, including the time needed to reach normal speed.
    On the average 2 km of a bus trip made by a rider the bus would stop 20 times, losing over 8 minutes! With a stop every 400 meters the same distance will be made by the bus 6 minutes faster, cause only 2 minutes are lost at bus stops. You have to walk in average 75 meters more to and from the stop (so 150 meters in total), given that the distance to walk from the side streets to the street carrying the bus line will be the same. Cause with 400 meters stop spacing the maximum walk is 200 meters, the average 100 meters, minus the average 25 meters you need in comparison for the alternative bus stop spacing of the 100 meters spacing system. Those 150 meters extra in comparison to the 100-meters-system translate in about 2-3 minutes extra walking time, but you save 6 minutes on the bus.
    So you win in total about 4 minutes. And you have, on board of the bus, the feeling it is moving and not crawling.
    Any objections?

  23. 8Dave November 7, 2010 at 8:04 am #

    The diagram with non-optimally overlapping diamonds assumes – falsely – that transit must follow the grid lines. Transit can be made to run 45 degrees off the grid, either by running below (e.g subway), or above (e.g. gondola). This leaves optimal corridors with no overlap and no coverage gaps.

  24. Cap'n Transit November 7, 2010 at 9:08 am #

    PlannerMunich, I’m talking about an existing system that works. On Fifth/Madison the Limited buses stop roughly every 650 meters. The Limited stops are all at major transfer points or destinations, so they have more passengers.
    In practice, there is very little transferring from limited to local or vice versa. If people at a local stop are in a hurry, they’ll walk to the limited bus stop. If people at a limited stop are in a hurry, they may take the first bus that comes along, depending on how far they’re going.
    As far as frequency, there are four overlapping services, each with about ten-minute headways, so that in any ten-minute period you’re likely to get one limited and three locals. You’re welcome to browse the schedules and ridership data for the M1, M2, M3 and M4.

  25. Jarrett at HumanTransit.org November 7, 2010 at 12:17 pm #

    @ hallam.jon.  No, 400m is way too close for parallel lines in most cases.  Geometrically, if you want zero duplicate coverage, and for the diamonds from one line to completely fill the coverage gaps of the other, you'd do lines 400m apart but a stop spacing of 800m, so that the diamonds of coverage on each route touched only at the points..  Nobody does that, however, in the real world, because it's usually more efficient (and necessary given street grid) for parallel lines to be much more than 400m apart.

  26. Jarrett at HumanTransit.org November 7, 2010 at 12:19 pm #

    @ 8Dave.  No transit system, not even subways, has complete freedom to go anywhere that ideal geography might dictate.  So you're right that in this case I was stipulating parallel lines because configurations of surface streets (and rail lines) often requires it. 

  27. TransitPlannerMunich November 7, 2010 at 12:32 pm #

    @Cap’n Transit:
    650 meters seem quite reasonable for an express.
    But when I calculate it right, the “express”, obviously a kind of substitute for a non-existing subway under Madison, has an average speed of under 12 kilometers per hour. Opposed to about 8 kilometers per hour for the local service. So it is slow versus very slow.
    Within Munich’s city limits the bus lines have a speed of 15 kilometers per hour to 20 kph. There is nothing slower. Despite a high density in the core city. The tram makes about 20 kph.
    I wonder what makes New York buses so slow. Still I remember crosstown buses that crawled with pedestrian speed along. After 10 minutes still the same person outside the window was walking in the same direction as the bus. That was depressing. And made you feel paralyzed.
    The ridership data itself is really interesting. Still, why are the costs so high? In a city here I would expect to have operational costs for a bus line of in average 60 to 120 Cents (US) per rider total costs, including investment. On some lines lower. And Germany is not a poor country.
    Bus drivers seem to make a lot of money in the US…

  28. Cap'n Transit November 7, 2010 at 1:13 pm #

    Things like this and this are what make New York buses so slow.

  29. hallam.jon November 7, 2010 at 1:37 pm #

    Hey,
    Oops! My mistake. I got confused between the ‘diameter’ and the ‘radius’ of the diamond. I’m having a brain issue. If those are the spacings for the ‘horizontal’ route stops (forming a grid pattern), is it better for the ‘vertical’ route stops to sit on the same grid (so a transfer can be immediate to a horizontal line), or is it better to offset them so they fall in the gaps (so that a choice of two horizontal lines are available)?
    hallam.jon
    Yours,
    hallam.jon

  30. TransitPlannerMunich November 7, 2010 at 2:31 pm #

    @Cap’n Transit: Yeah! I especially like the “walls of buses” cutting off residents from medical service, probably food supply and education too. Cause they will be unable to cross the street with this horrible transitway.
    The same fears were existing regarding a tram project in Munich. No one will ever be able to cross a street anymore cause of the constant stream of trams pouring down the street.
    All empty, of course, the transit agency loves to spend huge sums to operate empty trams just to be mean to the people.

  31. Alon Levy November 7, 2010 at 5:01 pm #

    New York’s buses do not have signal priority. They rely on signal optimization, which gives priority to north-south traffic, traveling at 40 km/h. When I’m in a taxi late at night on one of the one-way avenues, I go multiple tens of blocks without hitting a single red light. Of course, during the daytime, or on a bus, it’s impossible to keep up, so you always hit red lights once every few blocks.
    East-west buses are even worse, because there’s no optimization at all. Driving or taking a bus on such a street, you can expect half the lights you hit to be red.

  32. EngineerScotty November 7, 2010 at 11:06 pm #

    They should just connect all the trams together in one long circular loop, like a giant amusement park ride. 🙂

  33. In Brisbane November 8, 2010 at 2:04 am #

    What about bicycles? In cities with lots of cycling, would it be justifiable to have a slightly larger spacing?

  34. TransitPlannerMunich November 8, 2010 at 3:15 am #

    @In Brisbane:
    Even if you have a high proportion of cycling it does not mean that people would like to ride with their bike to the next bus stop. Some would, but the population is diverse. Most people who like to go by bike would use the bike then rather for the complete distance, if they cannot reach a stop by walking. Especially when the bus has an average speed of 10 kph or so.
    It makes public transport even more difficult, if you have to take care of your bike in addtion to the bus trip. And not everyone can ride a bike or wants to ride a bike, even if he has no car.
    Making bus stop spacing very wide (like every 1000 meters) and telling then the people to use a bike to get there sounds like a bad excuse for bad service. As if your local supermarket would put 5-meters-shelves everywhere saying it cuts costs and you do not need so much floor space to cross until you come to the product you want. And then offers you ladders to climb up to reach your favorite cereal. Maybe adding that climbing ladders is also healthy and a good compromise for everyone, a win-win-situation.
    To sum it up: If the distance to my next bus stop is so large that I need a bike, I personally would ride the complete way by bike or buy a car.

  35. Alan Robinson November 8, 2010 at 6:18 am #

    I’ve seen several comments here advocating for reduced stop distance on suburban routes. I find on these routes that drivers then have to accelerate and decelerate between each one of these stops in order to be able to both see and stop for a potential rider. This is made worse when:
    Where parked cars reduce the line of sight to the stop.
    At night with poorly illuminated stops.
    Drivers are unfamiliar with the route.
    This makes for both a uncomfortable ride and a feeling that the bus is going slower than it should.

  36. Alon Levy November 8, 2010 at 12:12 pm #

    re: suburban stops, here’s an illustrative story on what’s wrong with them:
    I was waiting at a bus stop in Hamden, Connecticut, to go to New Haven Union Station. The bus comes every half an hour, and was scheduled to arrive within 3 minutes; at the scheduled time, it didn’t arrive. It started raining, and the bus stop had no shelter, so I had to go about 30 meters back to wait outside a store that offered outdoor shelter. About 15 minutes late, the bus ran through the stop at full speed.
    I got to Union Station – by hitchhiking.

  37. Ben Smith November 8, 2010 at 8:57 pm #

    This is easily your best piece regarding stop spacing! If you map out stop spacing on most metro or LRT systems, it comes to about a kilometer – give or take.
    Also, it is a shame that here in North America we seem to afraid to expand stop spacing on local routes, since we could use the exercise and most would appreciate the extra speed.

  38. calwatch November 8, 2010 at 9:32 pm #

    Interestingly, TransitPlannerMunich’s comment is exactly why Los Angeles is cancelling half of its rapid buses. When you have a local bus running every 20 minutes and a rapid bus running every 20 minutes (or worse, a local bus every 25 and a rapid every 30), it hurts ridership dramatically. Better to start running rapid buses as needed once the local headway is more frequent than, say, every 12 or 15 minutes, and forgo the rapid buses during the other dayparts if local service drops below every 15 minutes.

  39. Zoltán November 9, 2010 at 6:03 am #

    “Interestingly, TransitPlannerMunich’s comment is exactly why Los Angeles is cancelling half of its rapid buses. When you have a local bus running every 20 minutes and a rapid bus running every 20 minutes (or worse, a local bus every 25 and a rapid every 30), it hurts ridership dramatically. Better to start running rapid buses as needed once the local headway is more frequent than, say, every 12 or 15 minutes, and forgo the rapid buses during the other dayparts if local service drops below every 15 minutes.”
    Quite right. I always thought it a silly arrangement to have rapids on those local routes. Such a high headway will clearly extend most journey times, as even for passengers at rapid stops, the faster journeys won’t come close to cancelling out the extra average wait.

  40. M1EK November 9, 2010 at 10:33 am #

    “Also, it is a shame that here in North America we seem to afraid to expand stop spacing on local routes, since we could use the exercise and most would appreciate the extra speed.”
    Ben, that attitude is why in so many NA cities, transit is the last resort of the carless and infirm. You don’t call your potential customers stupid and lazy if you want more of them. It turns out there are very good (objective) reasons why walks-to-stop over a certain amount turn off most people, and it has nothing to do with laziness.

  41. Nick November 9, 2010 at 1:16 pm #

    Zoltan and M1EK,
    Additionally, the LA Rapid buses are often no faster than the locals: Most riders waiting at a Rapid stop will take the Rapid (slowing it down as the fares are processed), allowing the local to skip that stop (speeding it up). I have often ridden in a Rapid that would pass and be passed by the same local bus many times in heavy, rush hour traffic.

  42. david vartanoff November 10, 2010 at 11:15 am #

    Signal priority is often mentioned, but at least in San Francisco and the East Bay(Oakland, Berkeley et al) the implementation has been slim and none. Even where deployed, it mostly is disabled or out of service.
    See p. 61 here
    http://www.actransit.org/planning-focus/projects-in-the-works/projects-in-the-works-3/ for a discussion of maintenance issues. As a regular rider of the line in question the system seems entirely broken.

  43. GD November 11, 2010 at 6:20 am #

    two comments from the point of view of a transit user who doesn’t know a local/rapid differentiation from his home system, or, for that matter, alternating stops on route-sharing lines:
    -these services add complexity to the system, and thus create problems attracting new customers, or being legible for otherwise transit-literate visitors. I know it’s kept me from using buses in several systems I used as a visitor
    -isn’t increased frequency one of the ideas perks of having several lines sharing parts of their route? If so, that advantage just left the building if they don’t serve the same stops. Or are my infamously horrid math-skills keeping me from understanding this properly?

  44. Ben Smith March 1, 2011 at 11:23 am #

    M1EK, I’m referring to having local bus stops every 400m like Jarrett suggests. Instead we have stops about half this distance, which does more to slow service to a crawl than to make the route more accessible.
    And once along a local bus route, if walking an extra 200m to the stop is a deal breaker, then you are fat and/or lazy*. Not to mention that you are probably just looking for an excuse not to use transit, and if it did stop extra close, then you’d probably still not take it because it is too slow (which is what happens anyways).
    *this does not include those with mobility problems, which is why most transit operators also offer a separate handicap service.

  45. Annonymous March 6, 2011 at 9:12 pm #

    I’m skeptical of so-called “threshold” models that assume a hard maximum walking distance. For example, if the model assumes a walking threshold of 1/4 mile, but the bus you need is 1/2 mile away, it assumes one would prefer to take a perpendicular for 1/2 a mile and transfer, rather than simply walk above the threshold to the direct bus.
    Any reasonable able-bodied person, however, would realize that it’s far faster to simply walk 1/2 mile to the direct bus and go that way.
    What this means is that the threshold-model is not really how people make decisions. People simply want to get where they are going as quickly and reliably as possible, and if an extra 5 minutes of walking saves 10 minutes of waiting at bus stops, then so be it.
    Walking also offers the advantage that it is far more reliable than any bus can ever be, as almost nothing out of your control can delay you. Furthermore, if you are in a hurry, or are cold and need to warm up, you always have the option to run all or part of the way.
    When you think at the problem from a time minimization standpoint, rather than a walking-distance standpoint, the optimal stop spacing becomes dictated by simple math, weighing the time saved by stops being further apart against the extra time walking to a stop.
    Are there exceptions to this? Of course. In some cases, extra walking can impose a safety risk in addition to a time cost, particularly along roads with high-speed traffic and no sidewalk, or high-crime areas late at night. For these cases, a walking threshold is indeed the best way to go, as it reflects how people would actually think. There is also the case of disabled people, who have strict limits in how far they are able to walk.
    Fortunately, each of these cases are relatively uncommon and are not the type of markets a transit system that wants to boost ridership should be going after anyway. Disabled people will always place a higher than normal value on the door-to-door aspect of private car transportation and will never consider using transit anyway, unless they absolutely cannot afford to get around any other means (including bumming rides off friends). Similarly, when a route has stops positioned on streets for which it is unsafe to walk, no one will ride it who doesn’t absolutely have to.
    For the common case – able-bodied people, walkable streets, safe neighborhoods, people are simply looking to get where they’re going the fastest and are not going to consider a stop out of reach because it’s 100 feet past the “threshold”.

  46. Max Schneider March 4, 2012 at 4:24 pm #

    This is exactly the reason why trams are so great (even though you do not like them)
    Because the necessary infrastructure for rail is so high, tram lines tend to follow mayor streets and tend to go in a straight line towards the destination. Which means that they actually take the short route, which makes them faster than most buses.
    Buses on the other hand take the scenic route because everyone and his dog want a stop right in front of their building/school/old people’s home/whatever and because they have political clout they get waht they want, which is lots of stops on winding, circuitous roads – and that’s why buses take forever to arrive.
    Furthermore: choice riders do get annoyed if the bus doesn’t follow the logical (i.e. short) route but goes for the scenic route because they compare bus service to their car. Trams on the other hand usually take the same short route you’d take in your car…