More ITDP truth-stretching

I wrote a lot last spring about the ITDP and their biased reporting on bus rapid transit. I thought I was done. I wanted to be done. And then I was looking something up and found this. More specifically, I found pages 23 and 24 and I just don’t know where to start. First on page 23:

BRT, however, has a distinct operational advantage over LRT: A BRT vehicle
can operate in mixed traffic on normal streets and then enter dedicated BRT
infrastructure without forcing passengers to transfer to another vehicle. LRT,
by contrast, can only operate where there are rail tracks, and passengers
coming from locations not served by the tracks must transfer to and from
buses, or to space-consuming park-and-rides, in order to use the system. 

This is just not true at all! A subway system can’t operate in mixed traffic. But light rail systems can—and do—all the time! Here’s an example from Boston. Here’s Pittsburgh. Here’s Philadelphia, San Francisco and Sacramento. And all of Toronto. Their big hit against light rail is belied by examples in many of the large cities in the United States! It’s just wrong.

And then there’s page 24. Oy, page 24. Here, they have a list of average speeds for different transit systems. The idea being, I think, is that look how fast some of those BRT systems are! Look, in Ottawa, the average speed of a bus is 50 mph. 50! That’s really fast. That’s basically faster than any transit service in the country. I’m really not sure what conclusions they’re trying to draw from these data.

And the data seem specious, and I looked in to where they got their data from. Which was from a footnote (well, really an endnote) 129 pages later in the document. They know no one is scrolling back that far (Al Franken—yes, Senator Al Franken—makes this point about Ann Coulter; see page 19). Here’s where the data is from:

12. Speed data is from the following sources: Ottawa, Interview
with Colleen Connelly, OC Transpo, 2012; Cleveland: Interview with
Michael Schipper, Greater Cleveland Regional Transit Authority,
2012; Las Vegas, ITDP, Recapturing Global Leadership in Bus Rapid
Transit, 2011; Pittsburgh, Interview with David Wohlwill, Port
Authority of Allegheny County, 2012; Eugene, Interview with Tom
Schultz, Lane Transit District, 2012; Boston, ITDP, Recapturing
Global Leadership in Bus Rapid Transit, 2011; Portland: Interview
with Jillian Detweiler, TriMet, 2012; Phoenix, Interview with
Abhishek Dayal, Valley Metro, 2012; Charlotte: Interview with Tina
Votaw, Charlotte Area Transit System (CATS), 2012; Los Angeles:
Interview with Gayle Anderson, Metro, 2012; Kansas City: Interview
with Randy Stout, Kansas City Area Transportation Authority, 2013

Let me get this straight. They got speed data—data!—from a bunch of reports they commissioned themselves and from interviews. If they got accurate data, it would be one thing. But these numbers are wrong! First of all, there’s no way that the average speed for the Ottawa transitway is 50 mph. And they asked people for an average speed, and people gave it to them, and they probably didn’t understand what an average is because the ITDP itself doesn’t understand what an average is.

Here’s a trip on buses which serve the Ottawa Transitway. It takes 55 minutes on the vehicle. The distance is about 25 km. The average speed? 17 miles per hour. Even an all-on-the-transitway trip takes 20 minutes to go 15 km. That’s 30 mph, which is better. But still nowhere near 50. Maybe they got their metric conversions confused?

Let’s go to the Charlotte Lynx. Does it average 35 mph? It runs 9.6 miles in 26 minutes. It averages 22 mph. Not 35. Pittsburgh? 9 miles in 22 minutes (25 mph).

And some of the low numbers are too low. They claim Denver’s light rail averages 14 mph. Even through the city center, it runs 14 miles in 38 minutes. That’s 22 mph. Phoenix? 23 miles in 65 minutes (21 mph). The Orange Line in LA—advertised as 11.2 mph—actually runs 18 miles in 57 minutes, at 19 mph. They’re even sandbagging the mode they want to push!

In any case, it turns out that a fixed guideway transitway—light rail or bus—will run at about 20 mph, stops included. The Silver Line in Boston is susceptible to traffic, but at low-traffic times it even makes 12 mph. How did I find these numbers? The Internet, from actual schedules and times. It would behoove the ITDP to actually do some research as opposed to just making numbers up.

What exactly is the ITDP’s agenda?

What, exactly, is the ITDP’s agenda, and why do they fight mode wars? They denigrate rail-based transit as if their opponents were well-funded machines slowly tracking over the world. In fact,, their “opponent” in the silly mode wars, is a small outfit in Austin which was originally founded to encourage light rail in that city, and doesn’t have the same funding or, agenda, it seems, that the ITDP does.

The ITDP says that its field of expertise is “Public Transport” but have a very narrow view of public transport: anything that doesn’t run on rubber wheels in a right of way doesn’t really count. This is really an open question: what is their agenda? Why not focus on better transit regardless of mode? Why publish reports with unsubstantiated statistics that don’t stand up to the light of day? Wouldn’t their argument be stronger if they reported the facts of BRT, and didn’t make up numbers?

As I’ve said before, I agree with a lot of what they say about the utility of bus rapid transit, but with one major difference. Bus rapid transit is an important part of moving people more efficiently, but only part of it. Buses, light rail and heavy rail transit each have their place, and need to be used where they are most appropriate. In a city like Bogotá, with wide boulevards and lower operating costs, BRT makes sense. In a city like Mexico, with gaps in a good rail network and relatively wide street, it does as well. In Cleveland, the HealthLine was likely a good investment in that corridor to spur development along the Euclid corridor. In Boston, BRT is certainly a good choice in some corridors. But, as I’ll flesh out in a final post in this series (yes, all things, good or otherwise, must come to an end), trying to shoehorn it in to certain corridors just doesn’t make sense.

I’d go as far as to say that the ITDP doesn’t really care about public transportation. They care about their bottom line. They want cities and foundations to pay them money to write reports using the metric they made up to analyze what they want to analyze. Good work, if you can get it.

How much does BRT cost? 7X less than LRT? (Hint: No.)

This is the third in a series about the ITDP bus rapid transit report for Boston, and the ITDP standard in general.

One of the claims often made by BRT propagandists is that constructing bus rapid transit is seven times cheaper than light rail transit.

This is from the executive summary of the ITDP’s Boston BRT report:

Analysis of recent transit development costs
in the United States suggests that implementing BRT in these
corridors would also be more cost-effective than other options
for improving the existing transportation system. Based on this
evidence, on average, BRT can be seven times more affordable
per mile implemented than light rail.

Their “Benefits of BRT” page repeats this factoid several times. Quite a ways down the page do they use some properly weasely language to qualify their statement: “BRT can on average be up to seven times more affordable than light rail.” (Italics mine.) Hey, guys? That’s now how averages work. An average is the sum of a set of numbers, divided by the total number in the set. It’s like saying “In February, Boston gets, on average, up to 65 inches of snow.” Boston must be a snowy place, a reader would say, since some there must be a lot of years that have more snow than that. Except “up to” denotes an outlier. Boston normally gets, in average, about 12 inches of snow in February. 65 inches is an outlier. The ITDP report is off by about the same factor.

If this seven-times-as-expensive figure were the case—especially in corridors where demand is not likely to exceed 2500 passengers per hour—then it would make a lot of sense to build, right? If you can get 25 miles of BRT for the price of four miles of light rail, it’s a no-brainer. But what about if you can get nine miles of BRT for the price of four miles of light rail? Because that’s the actual ratio: light rail comes in at slightly more than twice the cost. And the while the ITDP bandies about that number, they cite no actual evidence to back it up.

Given the capacity constraints of bus rapid transit, it becomes a harder choice: if you spend half the cost of light rail on a bus system that doesn’t have the capacity to serve the needs of the corridor, it’s wasted money. It becomes a sort of Yogi Berra white elephant: no one goes there anymore, it’s too crowded. Crowds seem like success, and they are, to a point. But overcrowded transit runs more slowly and is more prone to uneven headways. In other words, if you build it, and they come, then what?

* Planned for ~2020. Ridership includes 38, 38R, 38AX, 38BX
† Included significant grade separation/bridges/tunneling
‡ Primarily in an existing right-of-way
All dollar figures adjusted for inflation (2015)

I like charts (you’ll know that if you’re a frequent reader) and here is one. It shows the costs per mile, and daily ridership, for a variety of BRT and LRT projects which have been built recently. I included several Los Angeles LRT examples because it is the only city which has built both BRT (to the level of an ITDP standard) and LRT in that time, and included the much older (relatively) Blue Line because it was mostly built on an old Pacific Electric right-of-way, much like the BRT Orange Line. Is light rail more expensive to construct than bus rapid transit? Yes. Is it seven times more expensive? Certainly not. The distance-weighted average construction cost for light rail is about 225% higher than BRT, less than a third of the difference that the ITDP suggests. (I’ve left out rail examples here—the Central Link in Seattle, for example—which include significant tunneling or grade separation, and similar BRT systems.)

There is only one example of BRT construction which is seven times less expensive than any similar light rail line: the Emerald Express in Eugene, Oregon.

Eugene, Oregon The Emerald Express was cheap to build: but you get what you pay for. The line serves a transit system which has a daily ridership of 40,000; fewer than most of the light rail lines above. It runs every ten minutes—frequent by the standards of a small town—but will require significant more investment to go any faster. Why? Because many of its exclusive lanes are bidirectional: a bus may have to wait for a vehicle going the other way to clear. It’s like a single-track railroad with passing loops for buses. And the stations are not what you’d see in Bogota: here is one along a less populated stretch of the route. This is not to say that there’s anything wrong with the Emerald Express—it is good for the community it serves. But that type of infrastructure would be overwhelmed on opening day in Boston.

Oh, also: the second leg of the Emerald Express—with similar BRT features—is coming in a bit higher: $19 million per mile. So the one-seventh number? It’s pretty selective.

Los Angeles Then there’s the Orange Line in LA. It is certainly successful, relative to an unused corridor, anyway. It runs every four minutes and carries 30,000 passengers per day. It’s basically at capacity. It cost $27 million per mile to build initially (but the recent extension was more than $50 million per mile), and has a third the capacity of the Blue Line, built in a similar corridor. It wasn’t built as light rail because, well, it’s along story that includes Orthodox Jews and corrupt politicians. You can’t make this up. Since it’s over capacity, there are initial plans to improve capacity (costing another $20 million per mile) or convert it to rail ($65 to $95 per mile).

The cost for a bus line that will perform anywhere near the level of a rail line will wind up being just about as high, and will still have a much lower capacity—certainly nowhere near the 90,000 passengers the Blue Line carries. Of course, there’s a sunk cost issue. Having already spent $600 million on a busway, there’s an argument not to “throw this money away”. But the total cost for the busway could come to $1 billion by the time all is said and done, about what light rail would have cost in the first place, with a lower overall capacity. So the BRT is really a white elephant, even if it’s one that transports a lot of people. This is a perfect illustration of the problem I posited above: you spend a lot of money on a project and quickly it is overburdened.

Cleveland Perhaps the best example of a successful BRT line in the US is the HealthLine. It was built along six miles of Euclid Avenue from downtown east towards a university/hospital cluster (including, yes, the eponymous Cleveland Clinic, and Case Western, too). It carries about 14,000 passengers per day, and does so in a well-designed corridor (the only one in the US to qualify as Silver based on the ITDP’s standards). The corridor varies between about 70 and 90 feed wide. The cost? $30 million per mile. It was probably a good investment. There is a roughly parallel heavy rail line that makes the end-to-end trip faster, so there’s never likely to be very heavy corridor ridership, and it likely won’t have to scale beyond it’s single-lane capacity. Of course, this rail line has plenty of capacity (it is by far most lightly used metro system in the country) between the HealthLine’s endpoints, so there is a valid question as to whether these investments were necessary.

BRT boosters (ITDP) point out that the HealthLine has been the $5.8 billion of development which has taken place along the line. (Well, other sources put the number in the $4 billion range; it’s a big number.) Which is great. But two important caveats. First: correlation does not imply causation. Much of this development was planned out well before the line was built. Much of it likely would have taken place if no improvements had been made. It’s not like the Cleveland Clinic (with 1500 beds and $9 billion in annual revenue) waited for the bus line out front to be built. Or that Case Western—with a $2 billion endowment—didn’t spend any of it until the HealthLine was completed.

The comments by Coolebra in this article flesh this out very well, as does this article. As one commenter there quips:

I could probably go put a giraffe near the Cleveland Clinic, and surely the Clinic will build another building within the next 24 months (or two). I can publish a study showing that giraffe investment is the best way spur development as cities run around to put giraffes across their neighborhoods.

The point being: there are a variety of factors which account for the return on investment for any transit line. Crediting all of it to a single source is folly. And let’s all say it together: correlation does not imply causation!

Second: most of the improvements have taken place on the eastern end of the line. This happens to be where it mostly parallels the aforementioned Red Line rail line. Saying that all of the development in the area occurred because of the HealthLine would be like ascribing all of the development between Dudley Square and the Financial District in Boston to the Silver Line. It helps, but there are a couple other factors—and rail lines—involved.

So there’s nothing wrong with the HealthLine, per se. It is a decent investment and has room to grow. But there needs to be a bit more nuance in analyzing it’s ability to leverage private investment than claiming that anything built within a stone’s throw—a college campus and two major hospitals—is only there because of the BRT. (In fact, they’re there because of transit—originally, Euclid Avenue had a streetcar, of course.)

Hartford Very recently-opened is CTFastrak in between Hartford and New Britain. Like the HealthLine, it probably doesn’t have the capacity needs for a rail line, and there’s no existing light rail infrastructure in Hartford to build upon. It’s reasonably fast, mostly grade-separated, and serves both buses along the line and others that enter the line part way along it. (It’s brand new, but has been getting good reviews.) Of course, it cost $60 million per mile to build, which is comparable to most new light rail lines. It will probably score well when the ITDP comes to town (separate platforms, some passing lanes, etc) and they’ll probably gloss over the fact that it cost as much as a couple of sets of railroad tracks.

It might be a good time to point out another hidden BRT cost: maintenance facilities. Light rail costs almost always include the operating fleet as well as the cost of maintenance facilities. Most BRT systems makes use of existing maintenance infrastructure, at least to start, which reduces costs in the short run but in the long run will require more or larger garages to be built down the road, especially if the line is successful (the cost of the vehicles is usually included in the cost of the system). I don’t believe BRT costs have future maintenance facility requirements amortized in to their figures. Since these are likely shared with other bus operations, the costs won’t be factored in to the cost of the system. Such facilities can cost more than half a million dollars per bus, adding a million dollars per mile in costs for frequent systems.

San Francisco And then there’s Geary, one of the busiest bus lines in the country. It has more than 50,000 daily passengers spread out among four routes, the 38, the 38R (a limited stop route) and two rush-hour express routes, the 38AX and 38BX, which serve an outer portion of the line before using other streets to access downtown San Francisco. In a sense, these already function as a local-express BRT network, just without the bus lanes, stations and other amenities the ITDP looks for. So basically BRT, without the R. Do they function well? Hard to say. People seem to like the limited and express options (I mapped their Yelp scores a few years back) although at rush hour the 38R, which comes every four minutes, is at or near capacity (running 60 foot buses).

The city is planning to build BRT and have it “light rail ready” because they don’t have the money for light rail. The problem is that this is going to have the capacity issues that the Orange Line has in Los Angeles on day one. Yes, better platforms, signal priority and wider doors may help, but the system already carries more than 3,000 passengers per hour, so it won’t have the capacity in a two lane system. Much of it is being built as side lanes instead of in a center median, especially in the inner part of the route, so limited buses will be able to pass locals in mixed traffic lanes. But it won’t really solve the capacity crunch, especially if there’s traffic in those lanes.

There are two ways to add enough capacity on Geary. One would be to build light rail. A three-car light rail train every five minutes would carry 6000 people per hour and not be at capacity. The second would be to build a full-on four-lane Bogotá-style BRT system. The corridor already has local, limited and express buses: at rush hour, there are nearly 60 buses per hour serving the corridor. This would allow buses with different service patterns to skip stops easily, and as we’ve said before, a multi-lane system does have capacity that will match light rail.

There are only two issues. The first is that even the half-baked BRT system will cost $50 million per mile (and run in to the same white elephant/sunk cost issue as LA has). A four-lane system would likely cost more, getting in to the range of the average light rail system. The second is that while there is enough space on the street for this type of system, there’s not much to spare. Geary is about 100 feet wide—one of the widest streets in San Francisco—but it is still narrow compared to most streets in Bogotá. Since most highways in the City were never built (or removed) and these few rider surface streets, it functions as a thoroughfare, as well as a shopping street. So to take four lanes plus stops for a busway would leave only 35 feet or so on each side, barely enough for one lane and parking. This likely wouldn’t fly, so you get single-lane BRT: pretty expensive, but minimal improvement to capacity. The B-Geary was one of the last lines in San Francisco to lose streetcar service, and the only way to keep enough of the road for cars and have enough transit throughput is a light rail line, even if it would cost more. BRT is, to quote Sarah Palin, lipstick on a pig.

Minneapolis-Saint Paul There are several light rail lines which have been built as well; for some of them there was a conscious choice made between bus and rail transit. The Green Line between Minneapolis and Saint Paul is one. When it was proposed, bus rapid transit would have cost about a third of the cost of rail. But it’s unlikely that it would have been able to handle the passenger loads that the rail line carries, especially since it serves both the University of Minnesota (with 50,000 students, one of the largest in the country) and both downtown Minneapolis and Saint Paul (Minneapolis being the larger traffic generator). The line already carries 35,000 passengers daily—more than the ten-year-old Blue Line (which was built along an already-cleared but never-built freeway right-of-way)—a year in to service. With those riders, Minneapolis now has the highest ridership of any light rail system opened since 2000.

It also serves the Cities’ main sporting arenas (the ballpark, hockey, basketball and both football stadiums and the minor league ballpark; and yes, the Twin Cities may be the most over-stadiumed city in the country), so in addition to heavy loads at rush hours, it has to cope with frequent event traffic as well. If it were a bus rapid transit system, it would have been overloaded from the start. As a light rail line, it can cope with demand with 10 minute headways at all times (except overnight, and, yes, it runs 24 hours a day), which means it could easily double capacity—or more—if ridership increases.

Which is not to say that the Twin Cities don’t have any bus rapid transit. They have a couple of freeway-based lines (which don’t really conform to ITDP standards) and are planning several arterial lines, which may not have exclusive lanes but will have better stops, all-door boarding and more frequent service. One, on Snelling Avenue, intersects the light rail lines near both lines’ midpoints. While Snelling once had a streetcar, it probably wouldn’t merit one today, but it connects the two rail lines and will provide an important link in the region.

While the Twin Cities may be somewhat light rail-heavy in their planning, they are choosing appropriate modes for each corridor. They aren’t hamstringing heavily-used routes with inadequate BRT because it’s cheaper (or because buses are always better, or something) but aren’t spending on light rail where BRT will do the trick (the streetcar plans are another story, and how I feel about them—conflicted—is the topic of another post entirely). Rail cost more than twice as much as BRT would have (but certainly not seven times as much) on University Avenue. But it provides more utility than BRT on day one, with room to grow. It was a smart investment, and the right choice.

I’m more familiar with the Twin Cities than other regions, but imagine there are others which act similarly. But the ITDP wouldn’t give them the time of day and certainly doesn’t examine rail systems as “gold standard” or otherwise. Perhaps it’s time we took a more holistic approach towards analyzing transit investments—looking at ridership, throughput and actual costs, not hyperbole—rather than engaging in mode wars (the Transport Politic made just this point recently). Let’s choose the right mode for each corridor, not blindly push for one over another based on preconceived agendas.

What is the actual capacity of BRT?

This is the second in a series about the ITDP bus rapid transit report for Boston, and the ITDP standard in general.

When proponents of Bus Rapid Transit—

You know what? I need to redefine this. I am a proponent of BRT. But I am a proponent of BRT in context. When the ITDP talks about transit, they only mention BRT. Heavy rail, light rail, commuter rail, these are seen as competition, and need to be denigrated whenever possible. BRT is the solution, anything else is not even worth mentioning. 

This is myopic. Bus rapid transit is a tool, but just a a tool box needs more than just a hammer, transit needs a variety of modes working together depending on a city’s existing infrastructure, needs and geography. BRT needs to be used where and when it is appropriate, but it is not a one-size-fits-all solution for every transit need. I’ve already discussed how BRT is not particularly compatible with narrow streets, and how the cities used as analogs to Boston are anything but. 

—So to begin again:

When propagandists of BRT (yup, I went there, ITDP) talk about the benefits of bus rapid transit, they don’t tell the whole story. Their argument is that bus rapid transit has the ability to transport as many people as any other mode (45,000 per hour!), at a fraction of the cost. In very isolated cases, this may be true. However, they don’t mention that this is an extreme outlier. The infrastructure required for that number takes up enough space that it is compatible only in urban areas with long, wide thoroughfares with space to build. Without this, capacities are an order of magnitude lower, and BRT is much harder to scale than rail.

Here is what the ITDP shows for capacities in people per direction per hour:

This is somewhere in the neighborhood of being true (it’s, shall we say, rosy), but it shows absolute maxima, which for BRT are often attained in conditions which, in most cities, are unworkable. (Let’s also set aside the fact that 6000 people per hour on a non-BRT bus system equates to 1 minute headways, that a four-track metro like the 6th Avenue Line in New York runs at a capacity of 60,000 per hour and theoretically could run at 100,000 and that light rail is capable of more than 20,000 passengers per hour in, for example, Calgary. So, it’s basically not true then; see below.) The BRT number is from Bogotá, and it is an outlier. The way that Bogotá attains that number is by having the BRT system in the center of a highway with wide stations and two lanes for buses on either side, necessitating about 70 feet of street width. This requires four bus lanes at stations, and the street width to accommodate that something many cities just don’t have.

Without this width, BRT carries many fewer people. Bus and rail transit scale in two very different ways. Imagine (or look at the chart to the right) a graph where the X axis is the route, and the Y axis is the width of the corridor or the number of lanes/tracks. Rail scales along the X axis, by adding vehicles to the train, so that going from one car to 10 cars gives ten times the capacity. However, adding a second track (increasing the Y axis) only doubles capacity, there are no similar economies of scale. BRT can only lengthen the vehicle so much; most BRT buses top out around 100 feet (carrying about 160 passengers). However, doubling the number of lanes a BRT uses increases capacity by 10 times (or even a bit more; the most frequent route in Bogotá has 350 vehicles an hour—a bus ever 10 seconds!). So while rail can scale by an order of magnitude within a narrow corridor, BRT scales best in another dimension. However, this requires four lanes of width, plus stations, to have the same increase in capacity.

This becomes an issue when capacity is an issue. For a line transporting 1000 or 2000 people an hour, rail is no better than bus: a single-car light rail train every 8 minutes has about the same capacity as a 60-foot bus every 4 minutes. (This is assuming they have similar signal priority, level boarding and fare collection mechanisms to minimize dwell times and unnecessary stops.) Both these frequencies are show-up-and-go frequencies; the average wait time for a three minute headway versus a six minute one is a negligible 120 seconds, a small percent of total trip time.

But if demand increases, a rail line can easily add capacity while a BRT system can not. Increase demand to 3000 people per hour, and a rail line will handle it fine: a two-car light rail train every seven minutes does the trick. However, a BRT system maxes out around 60 trips per hour, and even at this point, even a minor load imbalance (say, from connecting services) or a traffic light cycle missed (say, to allow pedestrians to cross*) will cause bunching. There are diminishing returns at very low headways as being slightly out of sync can cause bunching and crowding issues. There’s a reason the BRT line in Los Angeles (the Orange Line) has four minute headways, and not less. Beyond that, bunching, and accompanying diminishing returns, are inevitable.

[Update: Mexico City has more frequent service, it’s just that Google Maps transit doesn’t show that. Thanks, Google Maps! And I didn’t go in to the GTFS file to see what was going on, and it’s a somewhat complex file! So, Mexico’s BRT system has higher throughput, especially given their longer buses, maxing out around 12,000 per hour. Of course, with vehicles every minute at-grade, bunching is inevitable as crossing phases have to be a certain length on wide streets, so speed declines. It’s certainly faster than minibuses in mixed traffic, which the system replaced.]

Beyond 3000 people per hour? A two-lane bus system has problems; crowding will increase dwell times, and capacity or speed may actually go down. A light rail line will reach this point as well, but will be carrying many more passengers when it does so. Boston and San Francisco run 35 to 40 light rail trains per hour underground, with a capacity of 15,000 passengers per hour (Boston, with some three-car trains, actually has a slightly higher capacity). Calgary runs 27 three-car trains (with plans to increase to four) through downtown at rush hour, at-grade! 27 four-car trains will give it a capacity of 22,000 per hour. (Their system carries more than 300,000 riders per day, higher than Boston or San Francisco.) That’s on par with pretty much any BRT system (Bogotá’s is over capacity, and they are actively looking to build parallel lines to reduce the demand on the main trunk routes.), but the stations and track only take up about 40 feet of street width, enough for a lane of traffic and wide sidewalks in an 80-foot building-to-building downtown corridor, still narrower than any BRT street in Bogota.

In any case, the chart that the BRT report has should actually look something like this, accounting for typical loads and outliers:

Typical loads are lines such as the Broadway IRT for the four-track metro, the Red Line in Boston for the two-track metro, a single branch of the Green Line for the LRT, and the Orange Line in LA for BRT. I took a guess at the typical throughput of a four-lane BRT; I couldn’t find any specific schedule or loading data.

Maximum loads are theoretical maxima. For a four-track metro, this is double a two-track metro (the 6th Avenue line is the busiest trunk line in New York, running about 30 trains per hour with a capacity north of 60,000, but could carry more). For two-track metros, several are in the 40000 range: the Victoria and Central lines in London (33 trains per hour, 1150 passengers per train), and the L train in New York (20 trains per hour, 2200 passengers per train). For BRT, four lane, the number is from Bogota. For light rail, the number is from Calgary, assuming they implement four-car trains as scheduled this year. And for BRT, two lane, the number is from a single-lane, one minute headway system with 100-foot buses (which don’t exist in the US).

Two notes:

  1. Bogotá’s system is an outlier. Most BRT systems carry many fewer passengers, especially the majority of lines which do not have passing lanes at stations to increase their capacity. While light rail can scale dramatically, BRT can not, unless the streets are wide enough. Which, in Boston, they’re not.
  2. Four-lane BRT is akin to four-track metros in capacity enhancement (a four-track metro can carry, in theory, more than 100,000 passengers per hour). However, a four-track metro is only necessary in very high demand situations; most two-track metros can be scaled to meet demand. Four-lane BRT, however, is necessary even when demand is well below what a typical metro line, or even light rail line, might carry. 

Here’s another way to look at capacity. It shows how different transit modes attain capacity: rail by adding vehicles (and, to get very high frequency, extra tracks) and BRT by adding passing lanes and frequency. It also shows a dotted line at 60 trips per hour—a one minute headway. Most systems operate to the left of the dashed line. In the case of rail systems, this is because more capacity is generally not needed. In the case of BRT, however, it is because the system is operating near its maximum. In reality, the lines should curve flatter beyond 30 trips per hour (except for four-lane BRT) as bunching and load imbalances cause diminishing returns.

In any case, it’s another way to show that while BRT is a useful tool in the transit toolbox, it has a very finite capacity unless it can be expanded to four lanes (plus stations). If you are trying to design a system which can scale, you either need to have that corridor space available (as is the case in Bogotá), or build a rail line. Without that, bus rapid transit can carry about 2500 passengers per hour, but it can’t scale higher.

[ * A note on pedestrians: surface BRT is constrained by the length of crossing traffic light cycles. Even with full signal preemption, a crossing cycle needs to be long enough to clear crossing traffic, and for pedestrians to cross the street. In most cases, a BRT corridor will be wide enough to require 30 seconds of pedestrian crossing time. At 5 or 6 minute headways, this is not a problem; the BRT only requires 10 or 15 seconds every two to three minutes, or so. At three minute headways, it requires 15 seconds every 90 seconds, and at two minutes, 15 seconds every 60, and at a minute, BRT requires half of the signal time. It is likely that buses at this frequency would, at times, be forced to stop because of the length of the pedestrian phase (and to keep cross traffic flowing at all), which would create bunching and crowding problems downstream. Again, most single-lane BRT networks operate at four minute headways, which constrains capacity. Beyond that, they lose signal priority advantages, which constrains speed. In other words, there’s a fair argument that for surface transit, a three minute headway may be better than a one minute headway.]

Boston will not have “Gold Level” BRT: the streets are way too narrow

I’m digesting the study from Boston BRT from the ITDP group (second installment on the actual capacity of BRT here) and while I certainly appreciate forward-thinking planning in transit, I feel that they are selling us a bill of goods in several respects. One is promising that Boston can cheaply and easily have a “Gold Level” bus rapid transit, a level attained only by a handful of South American cities. The problem is that Boston’s street geometry and grid does not allow for that level of service, even by the ITDP’s own scorecard. We shouldn’t marry ourselves to an artificial and unattainable standard, but we should build the transit system that we need.

The scorecard is out of 100 points, and you need 85 to meet the gold standard.

Here are the Boston BRT’s routes, and their highest possible scores (within reason, anyway) based on the detailed ITDP scorecard (sorry for the janky Blogspot table format):

Criteria Points Blue Hill Ave Dudley-Downtown Hyde Park Ave Dudley-Harvard Dudley-Sullivan Notes
Dedicated Busway 8 7 5 5 5 5 Assumes separated lanes for 75% of BHA, and colorized/exclusive lanes for 75% of other corridors.
Busway Alignment 8 8 5 5 5 5 Assumes an average of 5 points for corridors other than BHA.
Intersection treatments 7 5 5 2 2 2 Will be hard to ban turns across busway outside of Blue Hill Ave corridor. Assume some turns prohibited and signal priority.
Multiple Routes 4 4 4 0 4 4 No other buses use Hyde Park Ave
Demand Profile 3 2 2 3 3 3 Highly dependent on high-demand areas, which are often the most space-constrained. 
Center Stations 2 2 1 0 1 1 Center stations + lanes require 32 feet of width.
Station Quality 3 2 2 1 1 1 10 foot required width unlikely at all stations in narrower corridors.
Pedestrian Access 3 3 0 0 0 0 Requirement of 10 foot sidewalks rare in Boston.
Bicycle Parking 2 1 1 1 0 0 Standard of bike racks in most stations unlikely.
Bicycle Lanes 2 1 1 1 1 1 Some bike lanes qualify for one point.
Bicycle Sharing 1 0 0 0 1 1 Requires bike sharing at 50% of stations.
Systemwide 55 47 47 47 47 47 See Below
Total 8 82 73 65 70 70

Systemwide points assumes that Boston could qualify for full marks in a variety of categories, i.e. there are no physical constraints: operating hours (2), comtrol center (3), platform level boarding (7, although this may be difficult on downtown corridors), top-ten corridors (2), multiple corridors (2), emissions (3), intersection setback (3, assuming exceptions for frequent short blocks), pavement quality (2, although whether a 30-year pavement is attainable in New England’s climate is unknown), station distance (2), 2+ doors (3), branding (3), passenger information (2), accessibility (3), system integration (3).

Systemwide points where Boston would not qualify for full marks: fare collection (7/8, assumes full proof-of-payment system; otherwise it requires turnstiles at each station), express-local service (0/3, requires passing lanes), passing lanes (0/4, requires wider streets), docking bays (0/1, requires passing lanes).

Given these scores, the highest corridor scores 82, three points shy of “gold” standard, and that’s being quite generous in some categories (i.e., it will be tough to ban turns for most vehicles since there is not an adjacent grid which can handle the excess traffic, or squeeze in bike lanes in already narrowed corridors, and I’m still not sure why renderings along, say, Hyde Park Avenue don’t show stations, which take up a good deal of space). Two other corridors make the “silver” standard of 70 (barely), and the others are “bronze”. Even still, it would be a lot of work to shoehorn in enough ITDP-standard busway to meet that. Mexico City, which the report uses as a model, doesn’t even reach the gold standard on any of their lines, despite most of them running in streets wider than in Boston. In the US, only Cleveland has attained silver level, and Euclid Avenue there is mostly 80 feet wide (110 feet between buildings) and the narrowest parts are 60 feet wide. We need to have better-performing buses in Boston, but we need to adapt what works in other cities, not wed ourselves to a metric that is ill-suited to our city’s older, narrower streets.
I sketched the BRT networks in Bogotá and Mexico D.F., showing the curb-to-curb street width of each street where BRT operates. I divided the streets in to five categories:
  • 130 feet or wider. This is the majority of street widths in Bogotá. 
  • 100 – 130 feet. This is the minimum width in Bogotá except for two short portions: a narrow portion to a terminal downtown on a bus-only street (which is still 50 feet wide at its narrowest) and the southern portion, which runs non-stop through an undeveloped area to a terminal station. This is generally the minimum for passing lanes at stations.
  • 75 – 100 feet. This is the minimum width of most streets in the Mexico City network. Few Boston streets are even this wide. This generally permits single-lane stations, but not stations with passing lanes. This is the bare minimum width for a “Gold Level” BRT (although Mexico’s system is rated “silver”.
  • 55 – 75 feet. This is the minimum width of any BRT line in Mexico City. This is the minimum width for a complete street with two lanes of BRT, a station and either two lanes of traffic or one lane of traffic and bicycling facilities.
  • Less than 55 feet. There is no way to fit BRT on a street this wide without removing all but one lane of traffic. While BRT can run on streets of this width, they have to be in areas which do not require any auto access, and nearby streets need to be able to host adequate bicycling facilities. In a city like Boston without any street grid, this is impossible to provide. There might be a it of fungibility at the high end of this scale—something like the 53-foot-wide Harvard Bridge which could have a bus lane, a travel lane and a bike lane on each side, barely—but only in areas that don’t require any stations, at which point it’s just too narrow. 

One of these things is not like the other. Much of the supposed gold standard BRT route network in Boston is simply too narrow to have gold standard BRT. It’s also worth noting that while in Bogotá and Mexico BRT runs in relatively straight lines, in Boston, outside of Blue Hill and Hyde Park avenues, it’s much more serpentine. This is because of the cities’ unique geographies, and it doesn’t make sense to establish a single “standard” when each city is inherently different.

Here’s a fun game, called “where do you site the station?”
Because people do have to get on and off the buses somewhere.
Oh, and a street segment like this would require cars to turn
across the busway to access driveways.

In the ITDP’s 25 page report, here’s what they say about street geometry:

Boston has a unique cityscape, and while the ITDP analysis shows that
Gold Standard is possible, there are stretches where routing would pose a challenge. For
example, tight passages can still accommodate BRT, but in some cases a street may need
to be made BRT-only, or converted to one-way traffic.

By “stretches” I think they mean “pretty much everywhere.”

They also admit that it might be a wee bit harder to fit “gold standard” in Boston:

It’s important to note that all of these travel time projections
are based on implementing BRT at the gold standard throughout the entire length of the corridor. This study acknowledges that achieving every
element of Gold Standard in a few portions of some of the
corridors would require some bold steps. The exact corridor
routing and any associated trade-offs will have to be explored in
more detailed analyses in the future.

Yet their travel time savings analyses (appendix C, here) assume median bus lanes, which they state aren’t possible. This is—ahem—a lie. From Dudley to Harvard most of their savings come from congestion reduction:

Median-aligned dedicated BRT infrastructure
will greatly reduce the 20.6 minute delay associated
with congestion. 

Yet most of this corridor is too narrow to support median bus lanes and stations. (Not to mention that by analyzing the 66 they choose the longest possible Dudley-to-Harvard route—the 1, CT1 or Silver-to-Red Lines are all faster—and 66 bus schedules to Harvard include schedule padding for the loop through Harvard Square.) Yes, in theory, most of the corridor could have such lanes, but only if a single lane were left for vehicles, driveway access and loading, to say nothing of bicyclists. That’s just not going to happen, especially on that route through Brookline.

So, they acknowledge that street width might be an issue (read: probably impossible), but that’s something to be studied in the future, but the numbers assume that it’s a done deal. (More studies! More money for the ITDP!) This is intellectually dishonest. If something isn’t going to work, it should probably inform your study. This would be be like if someone studied a high speed rail line and said “do note that because we can’t plow straight through a major metropolis, the exact corridor routing might be slightly longer than analyzed” but then analyzed the straight line distance anyway.

Look at the maps above. Street width is a slightly bigger problem than they make it out to be. It comes down to the fact that the highest performing bus rapid transit lines are built in cities which already have a lot of room to work with. Boston is much less like South America or Asia (newer cities with wide roads) and much more like Europe (older cities with more constrained rights of way). There are not many ITDP busways in Europe.

More to come on such topics as where we should have BRT in Boston, how we should go about implementing it, and what we should implement in corridors where BRT is not workable. But suffice to say, we should not paint ourselves in to a corner by adhering to an arbitrary standard like the one from the ITDP.