Microtransit is Eating Science Fiction

A while back I wrote about Ada Palmer’s glorious science fiction series Terra Ignota, which I really do recommend to anyone with the slightest interest in philosophy, politics, or history.  But I called out one feature of her world that made me crazy: the fantasy that globe-spanning supersonic driverless flying Uber would enable people to make daily trips of thousands of miles.  These would abolish the constraints of geography (we’ve been promised this before) to the point that geographically bounded nations no longer made sense to anyone, and a fascinating new polity would be born.  This technology, as Palmer imagined it, was so flexible that you could take such a car from Chile to Paris and land right next to the preferred door of your destination, without tearing down half of Paris to create all this landing space.

This is less surprising if you attend a tech conference and realize how completely the tech elite has bought the idea that fixed route transit, like big buses and trains, is soon to be obsolete.  For many otherwise smart people it’s just a given that we’ll eventually all be in driverless cars that make different stops based on who’s traveling, and that in their highest form would always go nonstop, even though all those cars would never fit in anything we’d recognize as a city.  People have even gotten into The Atlantic proposing to drastically reduce the capacity of the New York City Subway by remodeling it along these lines.

Well, now I’m in the midst of Malka Older’s intriguing Infomocracy trilogy, and am sensing a trend.  This future Earth has the same flying cars (she calls them “crows”) although it’s clear here, as it is not in Palmer, that they are expensive to use.  For those who can’t afford them, though, there’s something like demand-responsive transit or “microtransit“.  In an early scene, we watch a man crossing Japan and notice the ruins of the Shinkansen, as though the new airborne services have abolished one of the most space-efficient (and therefore liberating) passenger services in one of the densest places the world.  When I try to make sense of this I can only assume that in this hyperconnected and hyperinformed world, there’s just not so much need for travel anymore.

But then I hit this, in Chapter 2 of the third novel of the series, State Tectonics:

The next morning, Maryam boards a commercial crow for La Habana.  It’s usually a good bet, since there are only a few possible stops between Doha and La Habana, but they get stuck with a stop in Praia, another in Montserrat, and three in eastern Cuba, and the journey is two hours longer than usual.

Demand-responsive transit has even replaced airlines, and it sounds like hell.  Everybody is riding little flying buses that make unpredictable stops on unpredictable paths, arriving at unpredictable times.  I would much rather change planes at DFW than ride a service that lets me stay in my seat but whose arrival time can vary by hours, not due to a disruption but due to the service working as designed.

Once she gets to her destination city, though, things are even worse:

Even once they arrive there’s a long line for municipal public transport crows, so Maryam takes a taxi.

It’s not quite clear what a public transport crow is, but the long line is a good bet that it’s more like a demand-responsive van than a fixed route bus, which means that its capacity is very low and it therefore generates lines at its stops whenever demand is high.  If there were a fixed route with a suitably big vehicle, all those people could board at once, though they might make some (predictable) intermediate stops and they might, when they got off, have to do a little bit of walking.  There may be crowds on fixed transit, but there usually aren’t long lines to board.  That’s the genius of true high capacity that comes only from a vehicle that doesn’t make a separate stop for every customer.

It’s remarkable how even science fiction writers whose values seem progressive just assume that the future of transport is so atomizing, inefficient, and unscalable.  Again, both Palmer and Older may be imagining societies so socially stratified that only an elite minority even use “public transport crows,” let alone taxis.  But it may also be that there’s just something demand-responsive in the air right now, something that makes it seem inevitable that the most space-efficient and energy-efficient transport services in the world are destined for the dustbin as soon as we get flying cars.

Science fiction futures are never built solely on science.  There are always gaps filled by the author’s imagination.  Both of these writers have done brilliant work, but it would just be nice to see more writers imagining different futures for urban transportation.  Because this one isn’t going to work.

UPDATE:  The author Malka Older replied on Twitter: [Her sentences flow across breaks between tweets so I’ve taken the liberty of formatting it all as a paragraph and adding links.]

since you tagged, I’m going to guess you’re interested in discussion, & clarify: transit is like that in the book not because I think it should be, but as a consequence of the fragmenting of polities. There are a lot of excellent results from the microdemocracy I describe but cities in particular lose a lot of economies of scale (often partially mitigated with coalitions) & ground transit in particular suffers from needing to cross multiple jurisdictions with separate governments.

This is exactly right. Older’s books are premised on a globe-spanning system of “microdemocracy” where the largest government unit is 100,000 people: a mid-sized US/Canada “suburb” or a UK/Australian “council”, for example.  In a big metro area these units are too small to lead the formation of an effective regional transport network — or to provide water, power, or most other urban services.  Older goes on:

Air and sea become more important. In book 3 we see an effort to revive long-haul trains, but it’s still something of a novelty. Also btw crows are a lot slower than Ada [Palmer]’s flying cars, slightly slower than today’s airplanes. My new book [The Mimicking of Known Successes] has more trains.  Although I think the coolest train system I’ve seen lately is in Annalee Newitz’s new book, The Terraformers. There’s a whole section on designing public transit. Also there are moose with gravity nets.

Moose with gravity nets!


23 Responses to Microtransit is Eating Science Fiction

  1. Jack February 10, 2023 at 5:20 am #

    Not having read the series, I’m curious if her tone is that this kind of public transport is a good thing, or if there’s some element of the narrative pointing out how negative the experience is as a result of this change, as a kind of commentary on it. Just from the quotes you chose, it sounds like while this is the future described, she is highlighting the problems. I’d be even more bothered if she described that future, but then described it as working perfectly.

  2. Dot February 10, 2023 at 4:38 pm #

    you literally just described New Jersey Transit ‘ s Access Link for the disabled.

    “Everybody is riding little flying buses that make unpredictable stops on unpredictable paths, arriving at unpredictable times.”

  3. Finthecat4055 February 11, 2023 at 8:15 am #

    Check out the Terraformers by Annalee Newitz. I just got to this passage:

    “We made a good faith effort, they would say. We got transit started and now it’s up to each city to carry on, they would add. And then, because most of the wealthy owners had private transit, there would be endless debates over where to plant those ugly tracks that Cylindra had already rejected. Nobody would want them next to their nice neighborhoods. There would be excuses about how trains messed up the Pleistocene purity of Sasky, but really it would be about not wanting to deal with the class of person who took public transit. Sulfur imagined the tracks slowly softening into mulch while millions of people tried to get around by cobbling together circuitous routes from dozens of local transit systems that each charged a separate fare.”

  4. ThatOtherOtherGuy February 11, 2023 at 10:53 am #

    How much energy is required to beam a person from the Enterprise to a planet’s surface and back? Why not use a fixed-route shuttlecraft with 30-40 people on it?


  5. Paddy Manning February 11, 2023 at 1:47 pm #

    The books are not the problem, the snarky, ignorant “progressive” writing the review is.

  6. Marc February 12, 2023 at 5:01 pm #

    What about micro transit in the real world? I take the LA Metro Micro service to and from work several times a week. LA Metro started their Metro Micro service after cutting fixed-route bus service to the point of un-usability for my trip. Is there a combination of density, demand pattern, etc where Microtransit can make sense?

    From my point of view, my trip to and from work is usually, but not always, faster than the fixed route bus. And, the service has improved coverage in the sense that walks are much shorter, and the service operates for more hours in the day, especially evening.

    Metro Micro will use a fixed route bus stop if it’s near the passenger’s origin or destination. But, in residential areas it will stop at certain designated corners if the bus stop is too far away. There are no signs on those corners, you are told the pickup and drop off locations through the phone app.

    The service can run late sometimes, on both the pickup and the drop off. But, I’ve seen improvements in reliability over the past six months.

    There are eight service zones around LA. I’m the the Pasadena zone.

    The Metro Micro service is popular in my area. LA Metro has recently increased the number of vans from 8 to 12 for my service zone. On the other hand, I’ve heard that adoption of the service is less in areas with lower tech savvy, so lack of smart phones skills, or the phones themselves, can be a barrier. LA Metro does allow booking rides by phone, but that apparently doesn’t make up for the smart phone issue.

  7. Sean Gillis February 13, 2023 at 5:48 am #

    “In an early scene, we watch a man crossing Japan and notice the ruins of the Shinkansen”

    Reminds me of Thunderbird, a British puppet sci-fi rescue show from the 60s. It’s set in the 2060s and there is a scene in the tunnels of the abandoned London Underground, which was replaced by some gadgetbahn that is briefly referenced.

  8. asdf2 February 13, 2023 at 8:05 pm #

    Like Jarrett, I personally like transit that runs on a known schedule that I can plan around. I also like systems that allow me the option to save time in exchange for a little bit of physical exercise. For example, if the bus that comes closest to me is slow and circuitous, I can walk further to a bus that is faster and more direct.

    With a microtransit system, you will get there when you get there, and there is nothing you can do, short of abandoning the system entirely, to get you there any sooner. Looking up schedules won’t help because there’s no schedule. Walking to a major road to get picked up may save others’ time, but it won’t save your time because you still have to wait for the same vehicle, regardless.

    • Jonathan Hallam February 14, 2023 at 1:51 am #

      Usually the app will demand everyone go to the main road unless they can’t due to, e.g. disability, so time is saved for everyone in that way.

      My home city, Milton Keynes, replaced a number of low-frequency coverage routes with this and it seems to have worked okay.

  9. Chris Lam February 15, 2023 at 3:23 pm #

    I think holoprojection à la Isaac Asimov’s Naked Sun is likely to become a better mode of socialising, working in teams and participation than physically jetting around in personal Ubers.

  10. Warren February 16, 2023 at 8:47 am #

    Most of your outlooks on transit from your first book is a large part the cause of the proliferation of Micro-Transit and by extension, greater autonomy to companies like Uber and Waymo. In part your apologetics for transit austerity, administration pay increases and redesigns that have actively reduced transit service around the world are behind Micro Transit everywhere.

  11. Onux February 16, 2023 at 1:50 pm #

    A couple of comments:

    1) The issue of space becomes irrelevant when discussing *flying* vehicles, because flight works in three dimensions not two. You do not need to demolish parts of Paris for flying cars to land, they can land in the existing roads for people to disembark. (I have not read the book but am assuming sci-fi flight technology, i.e. no need to accommodate jet blast) But the flying cars do not need to travel on those roads while heading to their landing point, they can travel above them – even if the number of people going to a particular street is ten times what the street can carry on the surface by having a vehicle flight path every 500 feet of elevation you could stack one hundred flight paths above that street. There is actually even more space than this because flying vehicles can use the space above buildings to travel, while surface vehicles can only use the space between them (roads). There are complications of course (crossing flight paths, the need to descend from high flight paths to the ground) but as someone who pays so much attention to geometry, to miss the fact that there is so much more space in three dimensions that two is a major oversight. The majority of traffic on any given street block in a city is not stopping at that block but passing by to another. If that traffic can bypass the “street” by flying above it, then there is clearly enough space for only those visitors stopping on that block to land.

    2) Abolishing the constraints of geography isn’t something that has been promised before, it is something that has happened before, many times in transportation history due to technology. People at the time of the introduction of the railroad considered locomotives to be almost like time machines with the way they could go as far in a day as it would take people weeks to walk. Tunnels and can bridges abolish geographic constraints and affect travel and political patterns – look at how the Oresund bridge/tunnel has affected commuting and employment matters in Copenhagen and Malmo.
    You state that daily trips of thousands of miles is a “fantasy”, however, thanks to jet aircraft many people routinely make weekly trips of thousands of miles, something would have been equally fantastic a hundred years ago when aircraft didn’t fly much faster than fast trains and had to stop multiple times to refuel for long journeys.
    Indeed the easy availability of intercontinental travel may already be creating geographically unbound polities – look at the way people on either side of the US political spectrum derisively refer to “flyover country” or “coastal elites.” A urban tech worker in Austin, Texas may travel more frequently to and interact with more people in the San Francisco Bay Area than they do with a rancher just outside the city, while thinking nothing of traveling to Paris for a vacation. That rancher meanwhile may relate more to Canadian trucker protests or the Gilet Jaunes than urban concerns.

    3) You express a personal preference for a predictable trip with a connection (the DFW bit) but this is not a trait shared by all people. There are also objective issues with your logic on the “predictable-route vs on-demand” debate.
    First, much research suggests that people do prefer staying in their seat instead of making connections, even if the trip is slower (although the connection penalty is normally not worth two hours, of course).
    Second, there are many reasons while a fixed route service can have unpredictable travel time not relating to disruption but the service working “as designed.” In the context of planes, the connection in someplace like DFW can vary by hours depending on your destination and travel time – because fixed route services get their efficiency by aggregating demand, you are not guaranteed a flight leaving immediately after you arrive. Similarly, your bus network redesigns you frequently result in networks with fewer direct services and more connections (“ridership” over “coverage”) yet if someone boards a 6 minute headway service and needs to connect to a 20 minute service they can be faced with a connection wait of from 0 to 13 minutes, which may be a significant portion of travel time, by design. Also for busses, while subways make predictable stops, since busses normally do not stop at stops with no passengers getting on or off, a bus journey can be variable by design if each of ten stops has one person boarding (versus five people each at two stops), or if several stops on a particular day have wheelchair riders requiring lift deployment, etc.
    Third, while an on-demand service as described may *sometimes* take longer than expected, from a games theory standpoint nine trips each of two hours and one trip of six hours in aggregate takes less time than ten trips each of two-and-a-half hours.

    4) High capacity public transit may not have long lines waiting to board (as you note, everyone can get on at once) but they almost always have lines waiting for a vehicle to arrive. From a passenger standpoint waiting ten minutes for the train to come, versus waiting ten minutes for everyone in front of you can board microtransit, is irrelevant.

    5) The biggest problem with your argument that microtransit is doomed to failure is that for close to a century we have been testing the theory of microtransit vs fixed route transit and microtransit has been decisively winning. The microtransit in this case is of course the personal automobile (aka “non-driverless” cars). The fact is that microtransit, whether personally owned or on demand, offers, in transit terms, zero headway, infinite span, express service. You in your own work have identified how lower headways and longer span increase freedom of mobility (the number of places you can reach in a given time) and the advantage of express service is self evident. It should thus be no surprise that the service that maximizes these qualities is the most used. In the countries with the best developed transit networks in the world (Japan, Switzerland) travel by car makes up over 50% of mode share. In countries considered to have excellent transit networks at both local and national scale (France, Netherlands) cars absolutely dominate, exceeding bus and train trips combined by 5 to 1 or greater. The constraints of geometry of course mean that there are areas where transit works where cars do not (Tokyo, Paris) but I still wouldn’t discount the growth of microtransit. From a geometric perspective, the ability to chain trips should have a huge impact, even if each vehicle served only two origin-destination pairs at a time (incurring the penalty of one maybe two intermediate stops) the effect of removing half of cars from the road would immediately eliminate congestion in all but the densest/busiest places (on-demand transit would also solve most of the geometric issue of parking, as vehicles move to the next trip at a destination, instead of stopping). From a rider’s perspective, there will be an inflection point where the time from extra stops for other passengers will be outweighed by the savings from stops skipped/a shorter wait because the vehicle came to you.

    6) Even if large vehicle fixed route transit is the *most* space and energy efficient, there are likely many (most?) areas where microtransit will be space and energy efficient enough, while providing the headway and express service benefits noted above to become the better transit mode. The places on earth where you physically cannot move the demand of people without trains on separate ROW are finite, and most people live outside them. Everything from small towns to mid-size cities generally have no real space constraints, and in many cases running a full size bus may be less energy efficient for the passenger load than several smaller vans. There was an example a few years ago of a Canadian city that subsidized free Uber trips for residents instead of starting a bus line. Urbanists criticized the program when it was oversubscribed and the city had to dedicate more funding, while totally ignoring that the original program was spending the same amount as the bus was going to, while having many more riders than the most optimistic bus predictions (to say nothing of the fact that service extended over the whole city, not just along the bus route). The city allocating more funding was a sign of success, not failure, and at least from a financial perspective buying Uber rides was more efficient than a bus. As above, there is probably an inflection point where in lower density areas the flexibility of microtransit outweighs space inefficiency. You probably discuss this inflection point quite a lot when consulting with agencies on how to allocate service – how much to ridership in high demand areas vs coverage to lower demand ones. Rather than denigrating microtransit as “not going to work” perhaps you should be having discussions with those agencies or running studies to see if coverage goals can be better met by subsidizing Uber/Lyft riders to/from certain neighborhoods, while leaving more funds to improve ridership goals in others (needless to say the mobility – how many places can I reach in a given time – for areas with subsidized on-demand trips would be greater improved vs one or two lower headway fixed routes that are slower and only go to stops on their route)

    6b) Note that many of the “future microtransit” benefits in regard to headway and span come from being driverless, which can be applied to fixed route transit too, allowing lower headways and late night service for the same or lower cost, but at that point with more vehicles per rider, there is an energy efficiency gain to going to smaller vehicles, at which point you are beginning to have the structure of microtransit without the advantages of on-demand service.

    • asdf2 February 28, 2023 at 12:33 am #

      I get what you’re saying, but I’ve personally had some pretty bad experiences with microtransit that have soured me on the whole concept.

      One form of microtransit that has existed for decades, is door-to-door airport shuttle vans. The first time I tried it, going 30 miles from the airport to my parents’ house, I got lucky. After 30 minutes of waiting for the van to show up, I was the first person to be dropped off and 35 minutes later (65 minutes total), I was home. The second time, I was not so lucky. 45 minutes of waiting before I could even leave the airport. Then, after leaving the airport, the van needed to drop off a bunch of other passengers before my stop. The passenger stops were in awkward positions, not really along a straight line, most of them requiring long detours from free to neighborhood arterials, to residential cul-de-sacs, to the drop-off point, then the reverse back to the freeway again. I spent about 2 1/2 hours on that van, hungry, thirsty, and nauseous, before finally getting home.

      The third time, I decided I was done with the shuttle vans and would just go home on the regular fixed-route transit system, figuring that if the ride home was going to take 2 hours either way, I could at least save some money by paying $1.25 for the bus, rather than $40 for the shuttle van. It was a three-seat ride, bus->rail->bus. The airport bus ran every 30 minutes, but it had a schedule, which meant that by controlling my walking speed and choosing whether or not to to stop at the restroom before getting on the bus, I could make the wait time 5 minutes, rather than 30. When I arrived downtown, I hopped off the bus and got on the light rail. With the light rail running every 6 minutes, wait time was almost nothing. The final connection was about a 10 minute wait for a bus that ran every 15 minutes – not great, but not terrible, and the door to door travel time ended up clocking in at about 1 hour 45 minutes – nearly an hour faster than the microtransit-like shuttle van for about 1/30th the price. (This trip was before Jarrett Walker was brought in to overhaul the Houston bus system; today, I think the travel time would be closer to 1 hour 30 minutes, thanks to some streamlined routing in the service restructure).

      But, even if one assumes that the 2 1/2 hour shuttle ride was exceptionally unlucky, and that the shuttle van is actually faster than the bus in the average case, even if you ignore the huge cost difference between the travel modes, riding the transit system just felt on the whole much less stressful. Riding the transit system, I know which route every vehicle is going to take, so I know when I’m going to get there and I know how much time is left. With the shuttle van, you have absolutely no idea what twists and turns it’s going to make next, and until the driver tells you you’re the next person to be dropped off, you have no idea when you’re going to arrive. With the transit system, even the connection points were welcome opportunities to stand up and stretch, and if you’re hungry or thirsty, the option is available to get off anywhere convenient, buy some food or water, and hop on a later vehicle to continue to the journey. With the shuttle service, I’m stuck on that van for 2 1/2 hours, not even able to get up and use the bathroom without feeling guilty about delaying all of the other passengers while they sit around and wait for me.

      I had a similar experience as a high school student, riding the school bus to school. The bus made lots of twists and turns picking up other students along the way, requiring a pick up nearly an hour before school started, to a school that was just 7 miles away. The bus was also often very late, and occasionally didn’t come at all. Eventually, I discovered that I could sleep 10 minutes later each morning by riding the regular fixed-route transit to school, rather than the yellow school bus – even though doing the trip with fixed-route buses often involved a connection. And, again, this Houston of all cities, not exactly known for great transit.

      It’s experiences like this that make me prefer fixed-route transit over microtransit, and I’ll only ride a dynamic routing service if it’s either the only option, or the fixed-route alternative is really awful, to the point where even worst-case zigzagging on the microtransit still offers a compelling time advantage. For short distances, where the choice is between a microtransit shuttle to go one mile, or simply walking the mile, I will nearly always just walk, and nearly always get there faster, since walking incurs no wait, no delays, and no zigzags.

      Another hidden time cost of microtransit that is often underappreciated is simply the overhead of logging into the app, telling it where you’re going, and ordering the ride. With Uber, it can take anywhere from 3 to 15 minutes just to get a confirmed connection to a driver, not including however long it takes the driver to drive to the pickup point. With the bus, I can pull out my app and know when the bus is coming in as little as 10 seconds, and if it’s a frequent bus, the odds of the bus showing up at the stop first, before the Uber car can get there are actually surprisingly high.

      I’m not going to argue that all microtransit is bad. There are some environments, particularly rural or semi-rural areas. I rode a microtransit vehicle once in a rural area outside of town, and it worked quite well there, with myself being the only person using it. But, in big cities, using microtransit as a substitute for real bus routes that carry hundreds of passengers per hour, simply does not make sense, with the possible exception of very late at night.

    • Dave March 6, 2023 at 7:32 am #

      If there’s little to no traffic congestion when operating in 3 dimensions vs 2… then why are many of the world’s biggest airports so congested and delay-prone now with just hundreds of flights landing there daily (instead of tens of thousands, like might happen if, say, a soccer/football game was occurring at a stadium at a specific date and time)?

      The existence of delays and congestion around busy airports when the people using them are packed in batches of hundreds inside each vehicle landing there suggests that there will also be lots of delays and congestion around each popular place when the people seeking to go to those places are landing in vehicles containing only a few people at a time.

    • RossB March 11, 2023 at 5:27 pm #

      So if I’m stuck in a typical traffic jam in a typical American city (that lacks good transit), I can put up my arms and say “We are winning!”. Here I was thinking it would be nice to have an alternative, like a subway line that got me to where I wanted to go much sooner.

      By the way, the main reason that private automobiles are so competitive with public transit is because we push the work onto the individual. If transit becomes automated, suddenly this huge advantage disappears. You aren’t paying the driver, and the fundamental cost effectiveness (and yes, space effectiveness) of fixed route, fixed time transport shines.

      • Alan March 15, 2023 at 2:40 pm #

        Private automobiles do impose non-monetary costs on the individual. But so do transit systems. In a private car, I have to operate the vehicle; but if I’m using transit, I typically have to get myself to a point on the system (walking or biking to a transit stop), probably have to adjust my schedule to match that of the transit system (adhering to the transit route’s schedule), and unless I’m lucky enough to be on a direct route I’ll have to spend some amount of time on a transfer. It’s also (typically) easier to transport *cargo* using a private automobile than on mass transit, especially if you have heavy or multiple items you have to move about.

        In an automated transportation world, where both fixed-route transport and private autos are autonomous, the former may have some cost advantages and certainly has space effectiveness. But the private auto will still have its own manifold advantages – door-to-door transport, at your schedule, without need for transfer or mode change, carrying cargo, and having more control over your immediate surroundings (temperature, noise, comfort, other people). In the cities that Jarrett focuses on in this blog (very dense urban metros), the space effectiveness may indeed predominate. But the “typical American city” doesn’t look like that. Most US residents don’t live in, or travel to work in the CBD of, very dense metros.

  12. Onux February 16, 2023 at 3:54 pm #

    Separating this discussion as my previous comment became so long.

    Although you are criticizing on-demand transit as being in opposition to fixed route transit, I believe one thing you should be looking at is transit that is both fixed-route AND on-demand. Far from being a misnomer, this is actually an incredibly common form of urban transit in the form of elevators. They are very much fixed route (they only take you up an down a single building, not to others) but they are very much on-demand (they come when you call for them and only go to the stops of people riding them).

    The obvious use case would be PRT style-systems like the one on Morgantown, with smaller vehicles and stations on sidings. There is no reason with current technology that a 10-car subway train coming every 15 minutes couldn’t be replaced with a single car coming every 90 seconds. This by itself would have a huge benefit from reduced headway, but stations on sidings would allow a rider to enter their destination when they arrive in the station and possibly see two vehicles pass by – with the tradeoff that the vehicle they get on will all have all/most passengers heading to the same/a close by destination, allowing many intermediate stops to be skipped. The combination of lower headway (3 minutes vs 15) and faster speed (average speed of urban transit systems is often half what the non-stop speed would be) would be a huge winner for overall travel speed and hence access.

    Moving to even smaller vehicles allows for some to be waiting on the sidings when passengers arrive, reducing headway to zero. There is a tradeoff here in system capacity, but I note that the Morgantown PRT operates in a hybrid fashion where some of the time it is fully fixed route (vehicles run constantly and make all stops) to handle demand. PRT gets a bad rap as a failed technology from the 70’s, but the Morgantown PRT sees ~4,400 daily passengers per mile, in a city with only about 60,000 residents including students, which is greater pax/mi than BART or MARTA.

    Another use case is for more traditional busses. No fixed infrastructure is needed here, instead a device that allows a rider to pick their destination on a given route when they arrival at a bus stop, and then a smart phone/tablet in the bus telling drivers which stops to make. The computer software would perform the work of dynamically allocating vehicles so that riders all going to a given destination all get on the same bus, and can again skip many stops along the way. Again, this technology already exists for elevators, with dynamic dispatch systems asking riders which floor they are going to, and then giving them a specific elevator to get on, thereby optimizing elevator use and speed (this in effect inverts the situation on traditional elevators – instead of the passenger getting on and telling the elevator where to go, the elevator system tells the passenger which elevator to get on based on where the elevators are going.)

    Such as system could eliminate the issue of bus bunching and gaps, although education would be needed to inform riders that watching some busses pass by will ultimately result in a faster trip. It also handles demand mismatch between center and peripheral areas. Instead of crude overlays (the #6 bus travels on Main St between 1st and 30th while the #6R goes from 1st to 10th then 30th to 45th, or the #6 stays on Main, while the #11 travels on Main to 20th before branching to Market) busses can be directed where needed. A bus dropping off its last rider travelling north can be immediately directed to turn around if there are many riders behind it wanting to go south, instead of dead heading to the end of its route. 25 busses may stay on Main from 1-2 pm with only 5 going to Market, but then from 2-3 pm each street may get 15 busses to/from downtown.

    Another level up from this would expect every rider to have a smartphone (perhaps subsidized for low-income residents) and enter their destination, and then the system would tell them which bus stop to go to, as well as which bus to get on. Many people already do a version of this with the OneBusAway app, choosing to walk three blocks to 5th St knowing a bus will arrive in 5 min, instead of walking one block to 1st St and waiting for 12 min. A more dynamic system could use the ability to walk a few blocks to send everyone heading downtown to 1st St, while riders going to the park are sent to 5th St, even if both routes serve both downtown and the park. At another level of complexity fixed stops on the route could be forgone for a flag stop model, where a rider at 3rd and D requesting to go downtown is told to go to 1st St while telling the bus to stop at D St to pick them up. Stopping every block is obviously not viable in a traditional fixed route plan, but stopping a few blocks in a row becomes viable if you know you will then run non-stop to a consolidated group of destinations. Another level up would dynamically shift busses between routes based on demand. Similar to the dynamic branching (Main/Market) mentioned above, this could involve telling some busses on the 1st St route to move to 5th for a few hours as needed, then come back.

    At a final level the system would be dynamic in two dimensions. A rider would enter their destination and the system would assign them to get on a bus that if necessary would be directed to stop and meet another bus that takes them to where they want to be (again, bus routes would be fixed, even if busses and bus stops are dynamic). Imagine a rider on 25th being told to get on a bus heading to Market, at Market they meet a bus heading downtown that won’t stop until it drops off riders at 5th and 2nd streets. Going home from 2nd, the rider may be told to walk to 3rd and Main, where they get on a bus that stops at 21st, 22nd, and then 25th, where a bus is told to stop and bring them back to their origin on 25th.

    All of these models involve larger vehicles, fixed routes, possibly fixed stops, and people walking a few blocks (in other words the key features of current model) to limit the complexity and space inefficiency of the anywhere-to-anywhere Uber model, while providing tangible benefits to riders. Uber/Lyft has been incredibly attractive for urban users, on top of the general dominance of personal cars in all developed nations. Disregarding the microtransit model as “not going to work” is dangerous when by some accounts it was taking ridership from the NY Subway, a place that geometrically should favor classic fixed-route transit over all else. Instead you should be looking at how the fundamentals behind on-demand microtransit can be used to improve more classic transit. Reduced headway/wait and faster travel are objectively attractive, the idea of “picking my destination” or “a vehicle that comes for me” may be subjectively attractive to the point it affects ridership. The various ideas I note (“on-demand-macrotransit”? “semi-dynamic”? “on-demand fixed route”? “ODFR”?) may be able to fully compete with microtransit, it may be competitive based on scale (low density areas get microtransit, medium density ones get on-demand fixed-route, high density ones get mass transit). Logic might dictate that in very high demand areas (Manhattan?) dynamic bus boarding might break down because there are so many riders boarding and alighting at each stop, but there could still be advantages to dynamic bus assignments (headway management, short turns, branch assignments). All, however, are much more productive to consider and discuss regarding the future of transit than assuming the current fixed-route mass transit model will remain superior in all or even any situations.

    • Dave March 6, 2023 at 7:39 am #

      You obviously have never worked in a really tall building where you’ve had to queue up for the elevator because upwards of 90% of the building is all arriving at the same “normal business hour” start time. Really tall buildings have to do all sorts of tricks to make the elevators work for most people at most times: things like assigning particular elevators to only certain floors, not making it easy to go from a floor in one part of the building to a floor in another part of the building without “transferring” on a “major” floor like the lobby… replicating all the hub-and-spoke features of many cities’ bus and metro systems, just vertically instead of horizontally.

  13. Henry Miller February 17, 2023 at 9:37 am #

    I’ve started to play with the idea of metrics for a transit system.

    Time below is door to door. Assumes a human at an walking average speed. For bike (and scouters…) it must be a full trip via that mode with bike parking, or there is provision for everyone to have it on the other modes (the bike rakes on the front of a bus do not hold enough bikes to count). For transit, assume worst case headway: you get to the stop/station just after it leaves.

    Door to door time for 90% trips of less than 15km should be less than 20 minutes. That 90% is there for the edge of the city where you may not serve farms at all, and also where other considerations make some trips not possible (ie it is too expensive to build a bridge crossing the river).

    All residences should have within 20 minutes: 1 supermarket equivalent (can be one large store, or separates: bakery, dry goods, caned foods, meat, dairy…); 5 restaurants, at least 1 of which isn’t a chain; 1 general medical practitioner; 1 dentist; 1 park; 1 public library. There is more that should be on this list. This is more of less the 15 minute city concept people are talking about, except that I’m allowing modes other than walking to be used, and thus it is relevant for suburbs.

    All destinations within 60km that are also in the MSA’s transit cache area are reachable in 1 hour. All destinations within 120km within the casement are reachable in 1.5 hours. MSA’s transit cache area means that if there is more than one transit agency they need to work together to enable transfers.

    There is of course room to debate the exact numbers above. Different cultures will have different needs (in India I wouldn’t expect you can buy meat near home), so some customization must be done.

    It will of course be very expensive to build the type of transit system that meets the above metrics. However note that a car meets all of the above, if your transit system can’t meet that level of serve a car is enough most people will just buy one if they can afford it.

    • Jonathan Monroe February 21, 2023 at 3:39 am #

      A car can’t do a 60km urban journey in an hour – urban speed limits are 50km/h in most countries and you will spend a non-zero amount of time waiting at intersections or in slow-moving traffic.

      An average speed of 30km/h on urban streets is VERY good going.

      • Henry Miller February 21, 2023 at 8:34 am #

        Every urban area I know of that is 60km or more across has highways that allow speeds of at least 100km/h (outer sections allow up to 130km/h) with no stopping at all. Sure you start out on urban streets that at much slower and have stops, but anyone who drives in such an area knows their best route to the highways and covers the most distance on those highways. There are also lesser highways where speeds are 60-100km/h, but there are stops every few km, which allows for faster average speeds.

        During rush hour you can’t meet the posted speeds, but if you travel the rest of the day there will be no problem.

        Maybe this is somewhat US specific, but it is reality.

        • Dave March 6, 2023 at 7:50 am #

          Hahahaha… “Every urban area I know of that is 60km or more across has highways that allow speeds of at least 100km/h (outer sections allow up to 130km/h) with no stopping at all.”

          Yes they *allow* speeds of 100-130km/h. Whether any particular car can achieve speeds of 100-130km/h at any particular time is highly dependent on how many other residents of the city (or people passing through the city from Elsewhere) are also on that stretch of highway. And in every city I’ve lived in (NYC, Chicago, DC) the time period in which 100-130km/h is actually achievable 100% of the time is limited to roughly 10pm-6am, and is dependent as well on the existence of special events. (For example, when a basketball or hockey game lets out at 11pm, I-395 in DC can be a mess.)

          Your faith in the ability to get anywhere 15km away at any time – outside “rush hour” as if rush hour in major cities is only a brief period in the morning and evening, the 10% exception I guess – in just 20 minutes amuses me greatly. Only ambulances with the sirens blaring can go 7.5km in 20 min in many of the world’s most heavily populated areas.

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