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Aleks Bromfield
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@EngineerScotty: Take a look at the "comparison" page for the "Ultra" PRT system (currently in use at Heathrow): http://www.ultraglobalprt.com/the-benefits/in-comparison/ The #1 item on their page is "convenience". Needless to say, if your objective function is "minimize wait time", a PRT is going to seem very attractive. That said, it's also very interesting to see this page: http://www.ultraglobalprt.com/wheres-it-used/heathrow-t5/ The airport has 67 million passengers per year, or over 180,000 per day. And yet Ultra serves only 800 passengers per day. Clearly, this is not competing with fixed-route transit.
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@ant6n: Rather than thinking in terms of ceilings or floors or other hard limits, I think it makes more sense to think about this problem in terms of relative efficiency. At any given level of mobility demand (above a certain threshold), it's more efficient to meet that demand using a highly-connected network of fixed-route services than by using any sort of flexible service. In general, most large American cities have less fixed-route service than they need, rather than more, at least in the urbanized area. (Conversely, outlying areas may have more fixed-route service than they need, often because local politics dictates that it would be "unfair" to provide more service to the city.) To the extent that flexible-route service replaces fixed route service in dense urban areas, it will almost necessarily make mobility less efficient in those areas. I doubt you'd argue with that. Now, to the extent that flexible-route service replaces private automobiles, yes, it would make mobility more efficient. But in my experience, there are two main reasons why people choose to drive in a large, congested city. First, they like the ability to come and go whenever they want. High-frequency fixed route services can inherently do a better job of providing this than flexible services. (And if you think people will happily board a bus that might drive a few miles in the opposite direction before heading to their destination, think again.) And second, there are reasons to drive that aren't directly associated with getting to your destination as fast as possible. Maybe you've got kids with strollers/carseats, or maybe you or your spouse needs a wheelchair, or maybe you're making a big shopping trip, or maybe you're heading to or from an area that has poor transit service. In all of those cases, even the best transit service in the world won't attract everyone out of their cars. (Even in Manhattan, I believe about 20% of households own at least one vehicle.) So realistically, it's reasonable to expect that flexible-route services will come at the expense of fixed-route ridership, rather than private automobile drivers.
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Wow, quick response! :) That makes perfect sense. I'd love to learn more about the psychology (if you could call it that) of biking. I'm a fit and healthy young adult, I own a bike, and I could easily use it for most journeys. But instead, I walk. Partly it's Seattle's hills, but mostly, I think that dealing with any vehicle -- even one as small and compact as a bike -- feels like a burden. The modes I use to get around -- walking, transit, taxis when necessary -- are all very "one-way" friendly. I have a sense that there are other people who feel similarly, and that it may be part of why biking doesn't have a bigger mode share.
Toggle Commented Jun 26, 2012 on just bought a house ... at Human Transit
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Congrats! Inquiring minds want to know: why did you choose a location with such a low Walk Score (by either measure)? Not to suggest that Walk Score is a perfect measure of anything, but even so, I'm curious why you didn't pick a more urban neighborhood. It's a personal question, so no need to answer... but you did bring it up ;-)
Toggle Commented Jun 26, 2012 on just bought a house ... at Human Transit
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Re flexibility: I think Jarrett's point is well-taken. Here in Seattle, people have a habit of arguing out of both sides of their mouth with respect to bus route flexibility. One person will say that Link (our light rail system) was a waste because it can't flexibly respond to changing demand... and they will turn around and argue against bus routing changes to meet Link, because they like their bus the way it is, thank you very much. It's not wise to change routing (or even frequency) every month to meet the slightest changes in demand, any more than it's worth it to change the bus fare every hour based on how many people are boarding. But many of our routes haven't changed since the streetcar era. For example, consider the 12. From downtown, it runs along Madison, a major commercial corridor. Then it turns onto 19th Ave, which was a major corridor back in the early 20th century, but is now a quiet minor arterial with some multifamily buildings and small businesses, but not much else. By all accounts, the 12 would do better to stay on Madison until 23rd (a major transfer point). The 19th Ave service sees very little use, and there is more frequent parallel service 4 blocks to the east and 4 blocks to the west. But because it's a trolleybus -- and because there are no wires on Madison between 19th and 23rd -- Metro has been very reluctant to change it at all. To cite another example, the 3 goes between downtown and the major public hospital/trauma center. It runs every 7-8 minutes during peak, making it one of the most frequent routes in all of Seattle. And yet the route it takes between downtown and the hospital is along a major I-5 entrance ramp. Thus, the bus often gets caught in highway traffic. This is an issue that simply wasn't relevant when the 3 was first created. But now, the time it spends sitting in highway traffic costs Metro a lot of money, and causes its users a lot of aggravation. As Jarrett says, after 100 years, activity patterns really do change. Neighborhoods grow and contract; highways get built; new industries develop. And system planning has also advanced since then; we understand more about what it means to build efficient networks. Should we reject all change at all just because someone might like things the way they are?
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Re dual mode buses: Changing from trolley to battery is easy, but many systems are designed such that changing from battery to trolley requires some sort of manual intervention. This could clearly be made easier, but for whatever reason, this doesn't seem to have been a priority for most trolley systems. Personally, I find this bewildering. Here in Seattle, where we have cheap hydroelectric power in abundance, wouldn't we get a huge savings if every local/rapid bus route could use electric power through downtown? If that could be automated, e.g. by having a "attach to trolley wires" button inside the bus, wouldn't the cost savings and environmental benefits be worth the brief stop? It's particularly agonizing for routes like the 8, 11, and 48, which run almost entirely underneath trolley wire, and yet use diesel buses exclusively because of the non-wired segments. Even more so when you consider that the 8 and 11 routes have very hilly segments without wire. Going up, electric motors would be a huge boon; on the way down, regenerative braking could actually *produce* energy.
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I agree with Michael that looking for a "tipping point" is the wrong idea. Just like walksheds, everyone has their own threshold for how long is okay to wait, and it can vary based on mood, weather, whether or not they're connecting, how far they're travelling, how far they have to walk to get there, how likely the vehicle is to be late, and how much they'll suffer if they miss their trip. To illustrate the latter point, consider air travel. Many people routinely arrive at the airport in time so that they have an hour between when they get through security and when their plane is expected to depart. Can you imagine arriving at a local bus stop an hour ahead of time? In my experience, 20 minutes is approximately the upper bound for what can be considered clockface service. If a bus comes every 20 minutes, then there will be some people, especially on a nice day, who won't bother to check a schedule before walking to the bus stop. On the other end of the spectrum, I've never met someone who wants a timetable for a service with 5 minute frequency. (But I have met many people who want a timetable for a train that comes every 7.5 minutes.) At least in Seattle, the ubiquity of real-time bus tracking (OneBusAway) suggests that 15-minute frequency is most definitely not freedom. Then again, the relative reliability of this schedule probably has something to do with it. For example, the 71/72/73 to the University District runs every 10 minutes, but is very unreliable. Without OneBusAway, most people would treat the service as random. But with OneBusAway, you can wait inside a warm cafe or store until you know that the bus is 2-3 minutes away. I guess the real lesson in all of this is that people hate waiting more than they hate following schedules.
Toggle Commented Dec 29, 2011 on how frequent is freedom? at Human Transit
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Here's what always gets me about PRT. People like to compare PRT to elevators. You press a button, it shows up, and takes you to your destination. But what people seem to forget is that elevators are not personal. If someone else is going to a similar destination, or even just in the same direction, there's a good chance that you'll share a vehicle with them. And elevators don't give you point-to-point service either! They take you to a single "transfer point" on each floor, and from there, you need to walk to your final destination. That said, I do think that elevators are a great model for public transportation. They're super-high-frequency, (so wait time is virtually nil); they have no human operators (so operating costs are virtually nil); and they're seamless (elevators feel like an extension of the floor). The closest analogy in the horizontal world are "people movers", like SkyTrain in Vancouver, or the systems that keep popping up in airports. The best systems, like the Plane Train in ATL, have vehicles which arrive every 2 minutes, and run side-by-side the pedestrian concourse, so that boarding and exiting are completely seamless. Airports are obviously specialized environments, but the same basic principles apply to cities as well. For example, many Montreal Metro stations are inside the Underground City. In most cities, no one would ever go into a subway station unless they wanted to catch the train. But in Montreal, people are already underground! (In many cases, you can actually see the trains moving from a vantage point well outside the station.) Metro is already mostly driverless; the operators simply close the doors. Unions aside, you could easily imagine automating the door closing, and increasing frequency to SkyTrain/Plane Train levels. And yet, rather than paradigm-changing improvements like these, PRT advocates keep trying to make trains into cars on rails. That's not Steve Jobs; it's a car company CEO who doesn't understand that the world is changing.
Toggle Commented Oct 8, 2011 on steve jobs vs. market research at Human Transit
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@Alon: It's not important whether express buses are profitable on their own, but rather, whether they save the system money. There are lots of ways that the latter could happen without the former. What it boils down to is that express bus riders pay a lot more for their privilege, and so as long as the extra cost to run express buses (instead of more local service) is less than the extra revenue from the higher fare, then express buses are worth running. It's true that I'm looking at express buses from a strictly economic viewpoint (as opposed to social equity, for example), but I think that's reasonable. From a social service viewpoint, express buses are never worth providing, because you could use that money to increase coverage instead.
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Anonymouse: With short enough headways, it's not a problem. I've spent a lot of time riding the Green Line (and some time in Seattle's DSTT), and it's never more than a 60-90 second wait for a train going *somewhere*. It's only when you want to go to one of the branches that you have to wait forever, ;) Brent: It's no mystery why modern LRT has wider stop spacing in the suburbs. The streetcar suburbs that were around when the Green Line was built are practically the inner city today. Even in Boston and San Francisco, newer lines (like the Braintree branch of the Red Line) have much wider stop spacing, matching the sprawling development of car-oriented suburbs. The lack of grade separation downtown is inexcusable, but sometimes you do whatever you can to save money...
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Re open busways, don't forget about Seattle! The DSTT is one of North America's most heavily used pieces of BRT infrastructure, but no one seems to realize it's BRT. Also, I think it's important to note that the advantages of open busways can apply to rail as well. This was more obvious back in the streetcar era, when every major street had a trolley, but it's still obvious in the remnants of those systems in older cities. In Boston, for example, the Green Line works precisely this way. Four local lines (Comm Ave, Beacon St, Riverside, and Huntington) come together into a single central tunnel. Inside the tunnel, it's a super-high-frequency subway; outside, it's a frequent local bus in (mostly) dedicated lanes that happens to run on rails.
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@Richard Emerson: The elevator example lends itself very well to PRT, since elevators *are* PRT -- except in very large buildings, they're on-demand, point-to-point service. They just happen to be vertical. This works, because elevators have very low per-ride costs (no operators, very little energy), and sparse demand (so you can have on-demand service without congestion). But for most cities which have bothered to build transit at all, the demand on transit corridors is already so high that any kind of PRT service would be overwhelmed. There's something to be said for *allowing* demand-responsive service. For example, King County Metro (Seattle) has a "night stop" policy of allowing you to exit the bus anywhere along the route, even if it's not officially a stop. You could imagine doing something similar for boardings, either with something high-tech (request a bus using a smartphone), low-tech (distribute reflective flags that passengers can use to wave down a bus), or a combination of both. But ultimately, those solutions only work for places and times with low transit demand. @Anne: You've perfectly described the problem space for commuter-oriented transit. If you make the same trip on a daily basis, then as you've pointed out, it's great to optimize for speed and to assume that people will consult a schedule. But modern urban life inevitably generates a number of spontaneous trips. What if I'm at home, and my friend calls me up and asks if I want to meet her at a coffee shop in 15 minutes? For trips like that, infrequent scheduled services might as well not exist.
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To me, it seems like there are only two reasonable criteria to use in designing a fare system. The first is profit maximization. Business (as a rule) don't set prices based on costs; they set prices based on what the market will bear. Prices are lower when there is more supply, and higher when there is more demand. By this standard, you would expect peak fares to be higher (since demand for travel is much higher), and long-distance fares to be higher (since competing travel modes also cost more). The second is incentivization. By charging more during peak hours, transit agencies encourage people to switch from overused peak service to underused off-peak service, which is a win for everyone. In many cities, peak service is almost overflowing, while service at night and on weekends is almost empty. The logical conclusion would be that peak service should cost more, and night/weekend service should cost less, or maybe even nothing at all.
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I have to say, I've never quite understood the opposition to trolley wires. When I first visited Vancouver, it was always a relief to see the wires overhead -- a very concrete reminder that I haven't yet civilization, and that no matter how lost I was, there was a bus that could take me home. Now, in Seattle, I picked my current apartment in large part because it was right next to a trolleybus (the 44). One thing's for sure: none of the people who are complaining have ever walked underneath an elevated train. Compared to the monstrous footprint of an el, trolleybus wires might as well not exist...
Toggle Commented May 10, 2010 on seattle: the end of trolleybuses? at Human Transit
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