What Is BRT Anyway
This is an issue raised by oceanstar17 in the full comment:
But we are talking about BRT
BRT is a different animal altogether. The logic behind BRT is to--taking the words from a GAO report on it--"think rail, but use buses". The idea is to have subway-like stations where a bus would stop at an at-grade boarding. The buses would come as frequently as a subway would with the same number of limited stops.
BRT proposals range from simple express bus service to actual lines that have their own right-of-way with subway-like stops. But in the end it's still a bus and won't attract the same patronage that a rail line would.
by oceanstar17 on Sun Sep 02, 2007 at 08:08:10 PM EDT
Of course, when any fancy sounding term can be applied to something with a poor existing "brand image", there is a tremendous incentive to over-use the term, applying it where it doesn't really fit, as noted in this comment:
Of course they aren't
Here in DC they supposedly have a version of BRT called the "Circulator". These buses run on the major tourist route in Georgetown and Downtown DC and are supposed to run so frequently that there is no schedule. But I've noticed that no one really rides the Circulator. It's attracted few of the promised riders. Yes, it isn't like the full-blown BRT, as it had to share the same right-of-way with cars; but it has at-grade boarding, limited stops, and very frequent service.
They did start something called "Metro Extra" on the 70 line on 7th Street NW/SW and Georgia Avenue NW. It is similar to BRT in that it has limited stops. That line has riders, but that is because there is no comparable Metro service that goes up Georgia Avenue. While the Green and Yellow lines run under 7th Street NW/SW, after the Shaw stop, they turn toward U Street and Columbia Heights before passing the Georgia Avenue/Petworth stop. Passengers going straight up Georgia Avenue still have to take the bus.
But the demographic that public transportation ideally is meant to attract from their cars--working suburban, affluent riders--will not ride buses. They will take trains, subways, streetcars, and light-rail. But they aren't going to abandon their cars to ride a glorified bus. The public has a strong preference for rail.
by oceanstar17 on Sun Sep 02, 2007 at 09:15:29 PM EDT
So ... what is BRT?
I'll start by breaking down the description in the summary of the Transit Cooperative Research Program (TRCP) Report 118, the Bus Rapid Transit Practitioner's Guide (pdf), which says (S-1):
WHAT IS BRT?
BRT has been defined by the FTA as a "rapid mode of transportation that can provide the quality of rail transit and the flexibility of buses." TCRP Report 90 expands this definition to "a rubber-tired form of rapid transit that combines stations, vehicles, services, running ways, and ITS elements into an integrated system with a strong image and identity." In brief, BRT is an integrated system of facilities, equipment, services, and amenities that improves the speed, reliability, and identity of bus transit. BRT is, in many respects, rubber-tired light rail transit (LRT) with greater operating flexibility and potentially lower costs.
The first "definition", from the Federal Transport Association is, of course, a slogan, not a definition. Whether BRT is rapid or not, whether it provides the quality of rail transit or not, and whether it provides the flexibility of ordinary city buses or not, are questions to be answered ... it is absurd to incorporate them into the definition.
The second, from TCRP Report 90, Bus Rapid Transit, is more to the point. BRT is a bus system with stations, guideways, and intelligent transport systems (ITS) that sets it apart from an ordinary city bus, and frequency that allows supports use without reference to a bus schedule.
Branding. It may seem odd that branding appears in all three definitions in this paragraph ... with the first definition being nothing other than a branding exercise for BRT as a whole. However, the broad stereotype in US society is that, by and large, ordinary city buses are a welfare function, provided for those who are either too young too be allowed to drive, are physically unable to drive, or are social losers. Unless BRT can success in separating itself from this stereotype, it can never succeed as a mainstream transit strategy.
Stations. In BRT, you do not wait at the side of the street, maybe on a bench, maybe with a little shelter from the rain ... you wait at a Station. And what is a station? Well, at the low level, its a bench, with a little shelter from the rain, and a ticket machine. However, the BRT bus shelter, from the pictures in the TCRP BRT Practitioners Guide, should have distinctive designs giving the impression of a mediocre modern sculpture ... this, presumably, is part of the branding exercise.
Busways. The third main element of BRT is a travel path that provide faster operation than is possible with a city bus. Of course, the main thing that slows down city buses is cars, so the simplest, cheapest busway to implement is a city street that has banned car traffic. This was the approach of Curitiba, where in the downtown area, every third city street was removed from the car transport system. Heavy planning and zoning controls targeted development to the transit streets, and the flanking streets were converted to one-way car traffic.
For some reason, the guide from the TCRP does not focus on this particular model, and focuses instead on a range of alternatives. The most basic is to place the buses on the arterial city street that a car would use for the selected line of travel, with bus priority priority features added to intersections. The next stage up is to add bus-only lanes to roads. The next step up is to add a dedicated busway to the road, such as in the median of a divided expressway. The ultimate is a road that has been built specifically for buses.
Intelligent Transport Systems. Intelligent transport systems is a grab bag that includes things from automated station announcements to automated positioning at the bus sto ... oops, sorry ... BRT station. However the most attractive ITS feature is time of arrival information at the BRT stations, which is often implemented using GPS technology on the BRT fleet.
Frequency. On Frequency, the Implementers Guide says (2-1):
Desired trunk line BRT headways should not be more than 8 to 10 minutes during peak periods and not more than 12 to 15 minutes during off-peak periods.
I have been a regular bus user in both Newcastle, Australia, and Portage Country, Ohio, on lines where the "low" frequency is hourly, and the "high" frequency is half-hourly. And I have also had the good fortune to occasionally use alternating routes in Newcastle with an effective frequency ... for my particular trip ... of quarter-hourly. And I very much agree with the guide, here ... if the frequency is less than ten minutes during peak hours, 15 minutes off-peak, its not BRT, not matter how well painted the buses, artistic the BRT stations, and grade separated the busway.
The minimum frequencies allows us to work out the baseline number of trips for a given route-mile along a BRT line. We do not have to give serious weight to multiple trips within a given route mile, as by design, stations are more widely spaced than city-bus bus-stops.
If there are three Peak Hours in the morning and three Peak Hours in the evening, and the BRT operates from 5am to 1am, this minimum frequency implies 92 services or more ... 36 peak and 56 off peak. 80% on-peak (crush) loading and 50% off peak loading would mean the equivalent of about 57 fully loaded buses or more in a given route mile. Raising the frequency to a preferred 6 minutes on-peak, 10 minutes off-peak would imply 144 services, 60 on-peak and 84 off peak, with the same loadings giving the equivalent off 90 fully loaded buses.
That give us a baseline/preferred of:
BRT versus Rail
- 3,420/5,400 with a 40 foot bus
- 7,410/11,700 with an 80 foot articulated bus
So that is BRT ... where does this nonsense about BRT versus rail come from? Well, it seems that it comes straight from the top. The Practitioners Guide says (S-1):
BRT can be less costly to implement than a rail transit line while providing similar benefits.
What does this mean, "loss costly to implement"? Well, it means a lower Cost to Buy ... but not necessarily a lower Cost to Own ... an issue that A Siegel has publicized on this site. Which, of course, goes toward explaining the bias of the Federal Government, and this regime in particular, toward BRT. After all, with capital costs supported by competitive project funding Federal Grants, while the operating cost subsidy is determined by a formula, a lower Cost to Buy allows the Federal Government to support more projects, while shifting the higher cost to own off on local and state governments.
Even the TCRP Practitioner's Guide implies that "similar to rail" means "similar but inferior to rail" ... however, it does so in a very subtle way, that is easily missed (S-4):
Common practice applies up to a 12-minute in-vehicle travel time "bias constant" for rail rapid transit. That is, the travel times for mode-split modeling purposes would be 12 minutes shorter for rail in comparison to local bus service. Accordingly, a maximum 10-minute bias constant is suggested for full-featured BRT.
This would seem to suggest that as a rule of thumb, the "extra appeal" of a BRT system is 5/6 of the "extra appeal" of a rail system. However, the "common practice" for rail systems implies that this is for a typical new rail system, rather than for an "ideal" rail system. On the other hand, the Practitioners Guide provides a framework for estimating how close a given BRT will come to their 10 minute bias constant ...
... so what this actually says is that, given equal time of trip, frequency, and other pure service factors, an ideal BRT system has, at best, 83% of the intrinsic appeal (that is, if both systems offer identical travel time from identically located stations) if a typical rail system.
Now, it should be stressed that there is no substantial evidence presented in support of this particular bias constant ... it is presented as a suggestion of the project team. So as I apply the evaluation of the TCRP "real world" BRT systems (3-23) to a typical rail project, I will include the comparison for the 10 minute bias constant and a more conservative 8 minute bias constant, where an ideal BRT has 66% of the "incremental appeal" of a rail system of equal service characteristics .. where "incremental appeal" is compared to an ordinary city bus.
The baseline, minimal BRT system has all-day bus lanes, attractive, lit stations, on-board ticket sales, unique vehicle livery and design, all day, high frequency, simple service pattern, passenger information at BRT stations, and BRT branding at stations and on printed information. This is estimated to achieve 43% of the appeal of the ideal BRT system.
The high level BRT system has a grade-separated busway, and in addition to the above features adds telephones, passenger amenities, and off-board ticket sales to the BRT station, has low-floor vehicles with multi-door access, and passenger information on the bus. This is estimated to achieved 95% of the appeal of the ideal BRT system.
So, compared to rail:
- with the TCRP 10 minute bias constant, the high level system has 80% of the incremental appeal of a typical rail system;
- with a more conservative 8 minute bias constant, it has 63% of the incremental appeal of a typical rail system;
- with the TCRP constant, the minimal system has 36% of the incremental appeal of a typical rail system
- with a more conservative 8 minutes, it has 31% of the incremental appeal of a typical rail system.
Now, consider that any BRT with a fully grade-separated busway can have a light rail system installed and, according to the BRT Practitioner's guide, gain a boost in patronage. Further, electric light rail is substantially more energy efficient than diesel buses, and without any modification of the light rail fleet will automatically inherit any improvement in the share of renewable power placed onto the electric grid.
Setting aside any biases built into competitive Federal Government capital grants, if the target is to pursue Energy Independence, why would you choose BRT over Light Rail?
The answer, I argue, is that we are not chasing a one-size-fits-all transport system to replace the one-size-fits-all auto transport system. One-size-fits-all never actually fits all, and for those it does fit, it fits poorly more often than it fits well.
And what is the "size" of a Light Rail route? On this, I defer to DoDo, who in Local Rail - An Overview gives the following advice:
Sometimes politicians treat light rail as if it were an alternative to subways or rapid transit, a cheaper alternative, but that is a bad idea to have. The busiest light rail line in the world, the one along the Grand Boulevard in my hometown Budapest, has a weekday ridership in excess of 200,000, but it is constantly crowded and relatively slow despite extra-long trams every 2-4 minutes.
Light rail is the right choice for ten to hundred thousand daily trips, not higher (or lower). With that, it could serve as the backbone of public transport in cities between 100,000 and 3-500,000 inhabitants. Above that, it is best used as feeder/distributor for heavier rail systems. For example, should the (already well-frequented) METRORail in multi-million city Houston expand from a single line to a real city-wide system, and induce a large proportion of inhabitants to switch to public transport, the addition of a proper subway or express railway would become unavoidable.
And there you have it. This is a lower threshold of roughly 10,000 daily trips for an effective light rail line. And what is the lower threshold of a BRT system? On the estimate above, something in the range of 3,400-5,500 per route mile would be a reasonable market for conventionally sized buses ... if the route has 50% turnover of seats, that is about 5,500-8,000 daily trips on the route.
With extremely long articulated buses ... well, 7,500-11,000 passengers per route mile with a 50% turnover in seats would be 11,000-16,000 daily trips, and over the lower threshold for a light rail system.
So, roughly speaking, a high level BRT will get us about 2/3 of the way from an ordinary city bus to a typical rail system, and do so at higher energy cost per passenger. And, further, upgrading the fleet to use substantially more renewable energy will typically require a further program of capital works ... at a minimum, and assuming a technological breakthrough in the productivity of biodiesel fuel stocks, implementation of heated fuel tanks to cope with low temperature gelling of biodiesel.
By contrast, a high level rail system will get us more than 100% of the way from an ordinary city bus to a typical rail system, do so at lower energy cost per passenger than BRT, and upgrading the fleet to use substantially more renewable energy can be pursued incrementally at the point of electricity generation.
This summarizes the critique of the implementation of of BRT on routes where a light rail system would be viable. And, of course, for replacing rapid transit, the idea is absurd ... a single double decker electric rapid transit commuter train can carry 1,600 seated passengers, the equivalent of the crush loading (seated and standing) capacity of more than 12 of the longest articulated buses.
And Yet, BRT still makes a lot of sense
It is easy to get so wrapped up in critiquing flawed arguments in favor of BRT that we forget valid arguments in favor of BRT.
First, BRT has proven itself capable of breaking into the mainstream, out of the "welfare bus" niche ... even in the supposedly transit-resistent US. From rider survey data, the TCRP reports 15% of Silver Line riders in Boston with incomes over $80,000 a year, compared to 8% on the comparable local bus route. Houston Metro services RCTR park and ride services found 70% of riders with household incomes above $50,000, compared to 11% of local bus rider, and 61% with two or more household vehicles, compared to 16% of local bus riders.
And, second ... readers of previous diaries may have been expecting this ... routes serving 5,000-8,0000 daily trips can be important recruiters for rail lines. The TCRP sketches of possible BRT line configurations give only one type integrated with a rail line:
... however, the merest brush with Route Matrix reasoning will suggest extending this to include cross-route BRT lines:
BRT and Rail Trail-Blazing
Of course, transit projects are evaluated based on current conditions. However, even the most optimistic real world assessment places Peak Oil within the next two decades ... which means that current conditions represent a very temporary state of affairs.
And this is what must be kept in mind when considering the strategy of trail-blazing rail routes, using BRT. This does not mean establishing BRT on routes that are at present appropriate for light rail. It means establishing a route that under current conditions is not appropriate for light rail ... but which will become appropriate if there is a shift in the relative appeal of cars and trains.
Indeed, this is why it is safe to establish a BRT route with a service level in the range of 5,000 to 8,000 daily trips. If crude oil price and availability conspire to push that into 10,000 to 16,000 daily trips, then that route should be converted to a light rail line.
And that same environment would then be pushing an ordinary city bus Express route from 2,000 daily trips to 4,000 daily trips, which can be pushed up to 5,000 daily trips by upgrading to it to a BRT system ... with the BRT fleet coming directly from the route that has been upgraded to light rail.
Best Isn't Simplest to Argue
Now, certainly, it is easier to argue that BRT is always superior to light rail, or light rail is always superior to BRT, or all we need is rapid transit and bikes, or ... well, any one-size-fits-all solution. When you have a declared loyalty to a one-size-fits-all solution, then you always already know the answer, and are always only looking for the arguing points and evidence that support your answer.
However, once we fall into that, we become victims of confirmation bias. Looking and finding supporting evidence and argument leads to supporters of other one-size-fits-all answers looking for and finding supporting evidence, which leads to the search for rebuttal arguments and evidence, and around and around and around.
And since one-size never really fits all, there will always be partial evidence to use in support of a number of mutually incompatible one-size-fits-all systems.
When we look at nature, we find relatively simple, homogeneous ecosystems, and relatively complex, diverse ecosystems. And looking more closely, the climax systems in a given bio-region are the ones with more complexity and diversity, supporting the greatest amount of biomass from the resources of the bio-region.
So that is my aspiration for BRT ... a transport system that fills a particular niche well, rather than an effort to provide a one-size-fits-all solution. Whether the current Federal Transit Administration under the current regime likes it or not, that's my story, and I'm sticking to it.