Bus Rapid Transit Stop Spacing: Is 2 Miles Too Far?

Joseph E asks an excellent question in response to my last post about the new Swift BRT, in Snohomish County north of Seattle.  Here’s the heart of it:

do you feel the wide stop spacing is a benefit? I was inclined to think the stations are too far apart. In comparison, commuter rail stops every 1 to 3 miles in most places (well, on the East and West coast), but always has an exclusive right-of-way, crossing gates, and high-speed operation between stations.

BRT should be capable of accelerating faster than diesel commuter trains, and obviously can stop much faster than even light rail. So why not have stations every 1/2 to 1 mile? It is much easier to walk 5 or 10 minutes to a station than walk to a local bus stop and transfer a mile down the road.

Arterial BRT can’t be compared to commuter rail.  It belongs in a space between ordinary limited-stop buses and arterial light rail.  And Swift is clearly at the lower end of that range: it’s running on the side lane, for example, where it will trip over turning movements, especially the zillions of driveway accesses into small businesses all along the route.  In such settings, high-reliability exclusive-lane service pretty much has to be in the median, and that’s clearly not what this is.

A recent Seattle Transit Blog interview with King County Metro’s Karen Rozenzweig here (hat tip: Pantheon) is helpful for defining the kind of service this is.  King County Metro, which serves Seattle itself and southern and eastern suburbs, is looking at a very similar product to Swift, called “Rapid Ride,” and she lays out the ideas pretty well.

So about the stop spacing.  Why not stop every 1/2 mile, so everyone’s within a 1/4 mile of a stop once they’re on the arterial?  The crucial fact of life here is that the distances people will walk vary quite a bit based on the quality of the service.  For a fast, frequent service that will take them long distances, many people will walk over 0.5 mi and some will walk much further.

So if you put the stops close together, you are helping to make sure you don’t miss anyone, but at the same time you’re providing duplicate coverage to the people who will walk further.  At the same time, you’re reducing the speed of the service and increasing its capital expense — especially on a system where the stations are really the main fixed-capital item.  Don’t be too distracted by acceleration and braking times; they don’t make that much difference at this scale compared to the number of stops.

Stop spacing ends up being very political, and varying based on local conditions along the route.  If you’re focused on long term urbanist outcomes, and are thinking about how the service will function once there’s been some redevelopment, fewer stops may be better, because you’ll concentrate development into nodes producing a more transit-efficient development pattern that supports the wide stop spacing into the long term.

Of course this is really bad for the people who are on the highway, a long way from a stop, not able to walk that far, and thus needing to use a local bus.  Good BRT planning looks carefully at densities all along the line, and tries to have this impact only where the ambient density is fairly low, which means there aren’t many of those people.  You’ll get need-based arguments from the people affected, but planners and politicians have to be trained to distinguish need-based arguments (I’m a nice person, and I really need the service) from demand-based arguments (we’re thousands of nice people, and we’ll use the service).  BRT is about demand.  Local buses and paratransit are there to serve needs.



15 Responses to Bus Rapid Transit Stop Spacing: Is 2 Miles Too Far?

  1. Alon Levy November 29, 2009 at 11:45 pm #

    The two most important attributes of commuter rail – speed and reliability – just can’t be replicated by a bus. If BRT wants to act like a metro, it should have the stop spacing of a metro, which is on the order of 1-1.5 km, not 3.

  2. Jarrett at HumanTransit.org November 30, 2009 at 12:22 am #

    @Alon.  <i>The two most important attributes of commuter rail – speed and reliability – just can't be replicated by a bus.</i> 
    Depends on the distance range.  Commuter rail has higher top speeds than buses given wide enough station spacing, so you're right, but that's only useful for long distances.
    Stop spacing is always contextual.  Even metros vary widely in stop spacing, often depending on the average trip lengths they're trying to serve.  BART for example is heavy-rail metro technology but has outer suburban stop spacings in the 3 mile range or wider, and in that landscape with such high average trip lengths you wouldn't want them any closer. 

  3. Alon Levy November 30, 2009 at 1:35 am #

    BART has just about the highest interstation of any metro in the world, and that’s because it’s basically an S-Bahn. And even then, its suburban configuration has made it an inferior service, especially in comparison with the Washington Metro. There are fewer passengers in Richmond and Fremont than in the Richmond District of San Francisco.
    For successful metros, 1.7 km is the outer limit of interstation spacing, as achieved in Moscow, Singapore, St. Petersburg, and some of the urban lines in Hong Kong. Unless there are water crossings or unpopulated regions on the way, there’s no reason to space stations further away than that.

  4. Joseph E November 30, 2009 at 11:13 am #

    “There are fewer passengers in Richmond and Fremont than in the Richmond District of San Francisco.”
    For those who don’t know the Bay Area, this is impressive because the cities of Richmond and Fremont have two BART stations a piece, while the Richmond District is over 2.5 miles from the nearest BART station and only has local bus service along congested city streets.
    Geary Blvd thru the Richmond District is one of the few places in the USA that definitely could support Heavy Rail / Metro capacity ridership even without redevelopment or higher gas prices. In fact, BART was supposed to have a line down Geary, continuing to Marin county, back in the original plan. But issues with the Golden Gate Bridge and Marin County’s lack of support for increased taxes killed that route. Now, Geary may get BRT for the meantime. Buses already carry over 55,000 rides per day on Geary Blvd alone (there are more on parallel routes), so improved service is desperately needed.

  5. Joseph E November 30, 2009 at 11:25 am #

    “Don’t be too distracted by acceleration and braking times; they don’t make that much difference at this scale compared to the number of stops.”
    Right. This is true for Light Rail or BRT, which has max speeds of about 55 mph and quick acceleration/braking (limited in regular operations by passenger comfort rather than vehicle performance. Acceleration great than 1 m/s or 2 mph/sec makes people fall down or get carsick).
    I mentioned “In comparison, commuter rail stops every 1 to 3 miles in most places” but did not elaborate. Commuter rail IS limited by acceleration rather than top speed. The diesel trains used by Caltrain and Metrolink in California take 1/2 to 3/4 mile to reach top speeds of 80 to 90 mph, and almost as long to slow down and stop. So it makes sense to keep stops at least 1 to 2 miles apart; otherwise you never get up to speed.
    Electric commuter trains, such as Metro North in New York, can accelerate at 2 mph/sec just like light or metro rail, but have top speeds of 110 mph in the USA (and perhaps 125 mph in some other countries). With the higher acceleration and higher top speed, you still need at least 1/2 mile to accelerate and 1/2 mile to brake, so stations closer than 1 or 2 miles apart really slow you down.
    But with BRT, we are up to speed (60 mph) in 1/4 mile, so stopping every 1/2 to 1 mile is not wasteful.
    I can agree with 1 mile station spacing. I am willing to walk 1/2 mile and it is an easy distance to bike. Also, many suburban areas only have perpendicular bus lines every 1 mile anyway, so people in between are used to walking that distance. But 2 miles between stations seems too far for pedestrians. At that distance some people are walking over 20 minutes and average walk time is 15 minutes, so 1/2 of passengers would be better off taking a local bus or bike for trips under 4 miles, and would likely have to take a bus and transfer, or bike to the nearest BRT stop, for longer trips.
    I agree that the cost of stations probably had a great deal to do with the spacing used. Hopefully, they will be able to add a few more in between, if warranted, in the future.
    Anyone from Snohomish county around? How is the reliability of Swift so far? Does it stick to the schedule? Would it be significantly faster with dedicated lanes?

  6. Alon Levy November 30, 2009 at 2:07 pm #

    For clarification, what I meant in my Richmond versus Richmond District quip is that BART would’ve gotten much higher ridership if instead of extending far out into the suburbs, it had served dense neighborhoods more, with a line under Geary and more intra-Oakland service.

  7. Mike B November 30, 2009 at 3:48 pm #

    I’m from Snohomish County!
    A few clarifications from a local who watched the system get built:
    -Swift opened yesterday, so its hard to say how its working!
    -Dedicated lanes aren’t too importatn as they’re already Business-Access-Transit lanes (right turns only except transit) along 11 or so miles of the route. The local buses never had a problem and they’ve been using these lanes for 5 years. The BAT lanes were paid for by the regional entity Sound Transit some years ago (I think).
    -The large 2-mile gap is a rather desolate industrial area with little residential zoning or transit ridership. Plans for infill stations do exist if the demand requires.
    Any questions about it, feel free to ask and I’ll try an answer!

  8. EngineerScotty November 30, 2009 at 4:39 pm #

    Mike–did you mean to comment on this thread, or the one on the Snohomish County “BRT” line?
    (BRT being in quotes not because I mean to criticize the line in question, but simply because I think the term is too slippery to use in this forum. 🙂

  9. EngineerScotty November 30, 2009 at 4:48 pm #

    Ignore the question in my last post–brain fart.
    One thing I did notice is that labor issues may have effected the level of integration between the transit agencies involved. Community Transit appears to be non-union, whereas the Everett transit district is unionized–and the union in question is mightily pissed that bus service is now present in their “turf” not being driven by their drivers. (The new service didn’t result in any lost union jobs).

  10. Ben November 30, 2009 at 5:54 pm #

    Jarrett, you REALLY should do an analysis on Toronto sometime in regards to stop spacing. The main east-west subway line stops every 700m (just under a 1/2 mile) outside of downtown. Keep in mind, Toronto’s urban area (both within the city limits and into the suburbs) covers massive amounts of area and is comparable to Los Angeles, New York, and Chicago, so less frequent stop spacing would be more beneficial.
    What is frustrating is that many “urbanists”, including the mayor, believe this stop spacing is ideal. They believe it so much, that the city is about to spend a BILLION dollars on a LRT “rapid transit” line through post-war neighbourhoods… with spacing at about 1/4 mile apart. Yes, you did read that correctly. They believe the stop spacing needs to be close to encourage pedestrian activity, and that those who do not live along the line have access to it (translation: we’re are going to slow down service for the people using the transit service for potential riders who may or may not use the service – and in the process make it unattractive to everyone).

  11. Ben November 30, 2009 at 6:01 pm #

    Would also like to add that the east-west line was built alongside a massive urban freeway network (which never was built). Maybe my tin foil hat is on too tight, but I believe that the thought behind the line was that only poor people would use it while everyone else would just drive. It would also explain why the stops look so bland compared to the older and newer stations.

  12. Alon Levy December 1, 2009 at 11:12 am #

    Ben, are there any extension plans for Bloor-Danforth that would work better if the line had had wider stop spacing?

  13. Ben December 3, 2009 at 7:37 pm #

    Re: Alon Levy
    Currently there are no extension plans for the Bloor-Danforth subway line.
    Toronto did look at extending it west into Mississauga a few years back, but found this to be a low priority. Essentially any extension to the west never got off the drawing board. If the stop spacing was similar to the Yonge-University-Spadina line with wider stop spacings (currently the only line looking at an extension), there may have been more pressure to extend it west.
    The east end of the line was extended, sort of. In 1985 the Scarborough RT opened, extending the line further east using Bombardier’s ICTS technology (same found in Vancouver and Detroit). Without getting into all the details… let’s just say that this line remains a textbook example of how NOT to build a rapid transit line to attract choice riders!
    Currently the only regional transit operator connecting with the Bloor-Danforth line is Mississauga Transit. The line does have some connections with two commuter rail lines, but ironically despite the frequent stops only two are actually connected to the station. The other two are about a 5 minute walk away from the stations. Nothing to cry over, but does seem somewhat silly. The Scarborough RT does connect to a frequent commuter/local bus connecting the eastern suburbs, but this bus also continues along to meet the north-south subway line, and ends up being far faster to take the bus to it to get downtown than to take the SRT-BD combo. Meanwhile not only do northern suburban transit routes connect with the north-south line, but so do ones from the northeast and northwest.
    While there are no plans to extend the subway, there are plans and funding to build LRT lines from the eastern and western teminus, and to convert the Scarborough RT to light rail as well. The west end line would be operated by Mississauga and would probably be built with proper station spacings. The eastern lines are to be operated by Toronto, and like the Sheppard LRT, is to have very frequent stops every 1/4 mile.
    One more thing: In defense of the Bloor-Danforth subway line, I could see the case of it operating like a “U-Bahn” while the Yonge-University-Spadina line operating more like a “S-Bahn,” though with “U-Bahn” qualities as it enters the core (like most rapid transit lines in North America and around the world). With that said, I question if a U-Bahn style metro line best suits Toronto’s needs and size.

  14. Alon Levy December 3, 2009 at 8:34 pm #

    Jarrett: the Munich S-Bahn is a rapid regional rail system, like the Berlin S-Bahn.
    And no, the Yonge subway isn’t an S-Bahn. An S-Bahn is typically characterized by sharing infrastructure and history with mainline rail; the Yonge subway doesn’t even run on the same gauge as Canada’s rail network. An S-Bahn or RER would have a stop every 2-3 km; the Yonge subway has a stop every 1 km, just like a metro.

  15. Ben December 8, 2009 at 7:48 pm #

    I am aware that the YUS subway isn’t an “S-Bahn,” I was just pointing out that it is better suited for longer commutes than the BD subway line. While the entire line averages 1km interstation spacing thanks to tight downtown stops, outside of the core the spacing is about every 1-2km, give or take. Meanwhile the BD line outside of the core is about every 700m and includes stops at local streets along with collector and arterial streets. This spacing can make the line unattractive to long distance commuters, but fine for short range travel through the inner-city (like a U-Bahn).