no, autonomous cars will not “abolish transit” in dense cities

Is transit headed for a collision with self-driving cars?  David Z. Morris in Fortune writes about how anti-transit Republicans are using the prospect of self-driving cars to argue against transit investments.

Alarmingly, he quotes nobody who can actually refute this argument, except in the fuzziest of terms.

Here is the recommended response:

We are currently in that phase of any new techno-thrill where promoters make grandiose claims about the obsolescence of everything that preceded them.  Remember how the internet was going to abolish the workplace?

In any case, technology never changes facts of geometry.  However successful driverless cars become, transit will remain crucial for dense cities because cities are defined by a shortage of space per person.  Mass transit, where densities are high enough to support it, is an immensely efficient use of space.

(Remember, a great deal of bus transit is in places where densites are not high enough to allow it to succeed; this is evidence of anti-ridership “equity” or “coverage” policies, not of transit’s failure.  Driverless taxis could certainly replace transit in those areas, assuming the pricing were gotten right, thus allowing transit agencies to focus on their core business.)

In many cases, people talking about driverless cars replacing transit are talking from an outer-suburban point of view, based on the experience of low-density, car-dependent places that are unsuited to high-ridership transit.  In those settings, if density is not increasing, they are probably right.  Driverless taxis will be more efficient than transit in these areas.

But all over the world, people are moving into dense cities, where even autonomous cars can’t replace a bus full of 60 people or a train full of hundreds.  There simply isn’t enough space to put walls between every pair of travellers, as the car model of transportation requires.  Nor will driverless taxis ever be there whenever you need them as great transit lines will.  Like bikeshare systems, they will experience surges where many of the vehicles are in the wrong place.

A city can of course choose to sprawl and avoid density to the point that driverless cars could dominate.  But in so doing it will fail to create a place that the 21st century economy will reward.  Real estate prices are already telling us that the market has chosen dense cities as the highest value form of development.  There is no dense city in the world that does not rely heavily on transit, for reasons of space-efficiency that none of the new technologies can change.  (Yes, autonomous vehicles will use space more efficiently than private cars do, but this is saying very little compared to what a great rapid transit network is achieving.)

Again, technology never changes geometric facts.  And the problem of cars in dense cities, and transit’s superiority there, is a geometric fact, a fact about space and its scarcity.


quote of the week: “rail is only part of the equation”


Trains would be just one layer of a comprehensive, multi-modal network that greatly enhances both neighborhood and regional accessibility for people all across the [Los Angeles] region. …

A singular focus on rail would divide the region into two: neighborhoods with rail and neighborhoods without. Such a future would perpetuate income inequality as housing costs rise near stations and station areas would be choked with traffic congestion. …

Getting our existing buses out of traffic is the quickest, most cost-effective means to bring high-quality transit to the greatest number of Angelenos.

Juan Matute, UCLA Institute of Transportation Studies
from a discussion called "Trains are Not the Silver Bullet"
 at ZocaloPublicSquare

This is from a collection of commentary about the the role of rail in the larger context of transit investment strategies.  Read the whole thing!






ioby invites you to “trick out your trip” via crowd-funding

Our friends at the Transit Center are supporting a new ioby project to crowd-source ideas about how to improve the experience of commuting. If you aren't familiar with ioby, they are basically a crowd-funding platform focused on small-scale neighborhood improvement projects. Have a look at the promo video for the project:

 Similar to better-known sites like Kickstarter and Indiegogo, ioby users are able to upload a project and create a funding goal which people who visit the page can contribute to. Examples of projects funded in this manner include community gardens, playgrounds, and environmental education programs, but now, ioby is offering a funding match up to $4000 for ideas related to transit. Have a look at the page for yourself here.

The guidelines for a project seem pretty open-ended:

1. Your project must do one of the following:

a. Be a non-digital tool that improves the public transportation experience, or
b. Focus on a single node within a transit system, but can be of any mode, i.e., a train station, a bus station, a bus shelter, subway or metro stop, bike share docking station, or parking lot, or
c. Encourage the use of clean transportation, in other words, have less environmental and social negative impacts than a single occupancy private car. Some examples include transit, bicycling, bike share, rideshare, carpool, car share, or vanpool.  We will consider modes and shared systems that aren’t identified here as long as they are less environmentally and socially harmful than a single-occupancy vehicle, or
d. Be something else in this spirit of the shared public transportation experiences! Talk to us! We don’t know all the great ideas out there! ([email protected])

On this blog, we focus to a great degree on what transit agencies can do to improve transportation outcomes in terms of network design and other aspects of the planning and operations of transit systems. But ioby's new project asks an interesting question: what small-scale, locally sourced ideas can people put into practice to make the transit experience more useful? 

Share your thoughts in the comments below, or better yet, head over to ioby and get your idea funded!

Email of the week: on Robert Steuteville’s defense of slower-than-walking transit

I don't have time to respond to everything that gets published on transit, but Robert Steuteville's must-read piece today on the Congress for the New Urbanism blog, which explains why we should invest in transit that's slower than walking*, certainly deserves a response.   

Fortunately, sometimes an email does it for me.  From Marc Szarkowski:

Hi Jarrett,

Perhaps you've already noticed this piece and are already penning a response (even though several already exist on your blog!). It seems to be another example of the "urban designers are from Mars, transportation planners are from Venus" phenomenon you described some time ago.

I admire and respect Robert, and I think his "place mobility" concept is quite sensible. Indeed, one can argue that the first and most powerful rung on the transportation "efficiency" ladder is to ensure that destinations are within walking/bicycling distance wherever possible, obviating the need for cars and transit in the first place, in turn freeing up the latter two for long-distance travel. But after the "place mobility" concept, I think the article begins to fall apart.

It seems to me that it's easy to romanticize slow transit if you don't have to rely on it all the time. With all due respect, I get the impression that many "streetcar tourists" use transit only occasionally when visiting a new city, or perhaps to go to a ball game, but for little else. And I get it: if much of your day-to-day travel is characterized by routinized, featureless car trips between work, shopping, meetings, and whatnot, I can see the allure in taking a break to relax and 'go slow,' as it were.

But the romantic impulse towards slow transit wears away quickly if you have no choice but to rely on it all the time! I don't have a car, so I rely on buses that travelexcruciatingly slowly, wasting much of my time. (I have, for example, learned to pad an hour between meetings and appointments in different parts of town, simply because the mixed-traffic transit takes so long to get from A to B to C.) So, rather than viewing slow transit as an opportunity to unwind and watch the street life pass by, I see it as a precious-free-time-gobbler. 

love to be immersed in street life when I'm walking, but when I inevitably need to travel beyond walking distance, I want to get there quickly. Does this make me a so-called "speed freak?" If so, wouldn't all the urban designers out there praising slow transit for others - while they hurriedly shuttle from charrette to public input meeting to office to daycare in their cars – be "speed freaks" too? The reality is that most of us – walkers, bicyclists, drivers, and transit riders alike – are "speed freaks" most of the time, simply because we prefer minimizing travel time and dedicating our precious free time to friends and family.

And this gets back to "place mobility:" it is great when many daily necessities – the grocery store, the bank, the library, the elementary school – are within walking distance. But – and this perhaps reveals a conceptual flaw in New Urbanism – not every place can or should be a self-contained "village." As Jane Jacobs argued, the whole point of cities is to offer rich opportunity – opportunity that requires travel beyond whatever a "village" can offer: "Planning theory is committed to the ideal of supposedly cozy, inwardly-turned city neighborhoods. [But] city people aren't stuck with the provincialism of a neighborhood, and why should they be – isn't wide choice and rich opportunity the point of cities? (Death and Life, 115-116)."

For example, I may be fortunate enough to have a daycare center on my block, but perhaps I want to send my kids to a magnet or private school across town – a school better than my neighborhood school? So would my kids rather wake up at 5am to take a streetcar sitting in traffic to get to school, or wake up at 7am to take a faster subway or a bus on a bus lane? I may be fortunate enough to have a pharmacy on my block too, but what if the doctor I trust is across town? Would I rather take the whole day off from work to take a streetcar sitting in traffic and delayed by a poorly-parked car to get there, or could I take a half-day by taking the subway or the crosstown express bus? For better or worse, there will always be long-distance destinations, and I suspect transit riders will continue to prioritize speed for these trips.

As for the short, local trips made possible by "place mobility," I still wonder whether mixed-traffic streetcars are the best bang for the buck. Yes, they are a placemaking tool, but they're not the only (or the cheapest) one. If, as admitted in the article, mixed-traffic streetcars don't particularly offer useful transit, nor are they necessarily the only/best/cheapest placemaking tool, then I have to wonder if 30 years from now we'll look back on them as yet another expensive urban renewal fad. (American cities are still littered with half-dead "game changing" fads from the 50s, 60s, 70s, and 80s.) We ultimately need rapid transit and "place mobility," but mixed-traffic streetcars are hardly a prerequisite for creating the latter.

So far I've hesitated voicing these opinions to fellow urbanists because I don't want to alienate any friends, but I'm increasingly skeptical of the streetcar fervor. Given that (A) mixed-traffic streetcars are simply slower and less-flexible than mixed-traffic buses, and (B) that the benefits that are packaged with properly-prioritized streetcars (dedicated lanes, signal priority, durable shelters, etc.) could just as easily be packaged with buses, I wonder if the streetcar fervor is an example of simple "technograndiosity." At the end of the day, I'd rather have ten bus lines reaching twenty useful places than one streetcar line reaching two useful places.

(Marc Szarkowski creates plans, models, diagrams, and illustrations of urban design, streetscape design, and planning proposals, and is a regular rider of Boston's, Philadelphia's, and Baltimore's transit systems.)

*Most new streetcars in the US have average scheduled speeds of 6-10 mph, a jogging or running speed for able-bodied adults.  However, actual travel time (compared to a private vehicle alternative) includes the average wait time.  Most US streetcars are not very frequent (usually in the 15-20 minute range) given the short trips that they serve, so it is the high wait time, combined with the very slow ride, that makes them slower than walking.  Again, this calculation describes the experience of an ordinary working person who needs to get places on time,  not the tourist or flaneur for whom delay is another form of delight

How good are we at prediction?

Transportation planning is full of projections — a euphemism meaning predictions.  Generally, when we need a euphemism, it means we may be accommodating a bit of denial about something.

Predicting the future, at a time when so many things seem to be changing in nonlinear ways, is a pretty audacious thing to do.  There are  professions whose job it is to do this, and we pay them a lot to give us predictions that sound like facts.  I have the highest respect for them (all the more because what they do is nearly impossible) but only when they speak in ways that honor the limitations of their tools.

Good transportation planning does this.  at the very least, it talks about future scenarios rather than predictions, often carrying multiple scenarios of how the future could vary.  Scenarios are still predictions, though; they're just hedged predictions, where we place several bets in hope that one will be right. 

I will never forget the first time that I presented a proposed transit plan and was told:  "that's an interesting idea; we'll have to see how it performs."  The speaker didn't mean "let's implement it and see what happens."  He meant, "let's see what our predictive model says."  You know you're inside a silo when people talk about prediction algorithms as though they are the outcome, not just a prediction of the outcome that is only as good as the assumptions on which it's built.

What's more, we seem to be really bad at predicting curves, or even acknowledging them as they happen.


Something really important happened in the US around 2004, which experts call the "VMT Inflection."  Vehicle Miles Traveled in the US — the total volume of driving — departed from a linear growth path that it had followed for decades, and went flat.  Here's the same curve looking further back.  Around 2003, you could be forgiven for thinking that this steady slope was something we could count on. 

VMT rising

(At this point an ecologist or economist will point out that the VMT inflection shouldn't have been a surprise at all.  This graph looks like what a lot of systems do when their growth runs into a capacity or resource limit.  The VMT inflection is a crowdsourced signal that the single-occupant car is hitting a limit of that kind.)

So reality changed, but the Federal projections didn't.  Even as late as 2008, when the new horizontal path had been going for four years, Federal projections claimed that the growth in driving would immediately return to the previous fast-rising slope.  Again:


This isn't prediction or projection.  This is denial.  

All predictions rest on the assumption that the future is like the past.  Professional modelers assume their predictive algorithms are accurate if they accurately predict past or current events — a process called calibration.   This means that all such prediction rests on a bedrock idea that human behavior in the future, and the background conditions against which decisions are made, will all be pretty much unchanged, except for the variables that are under study.

In other words, as I like to say to Millennials:  the foundation of orthodox transportation planning is our certainty that when you're the same age as your parents are now, you'll behave exactly the way they do.

We describe historical periods as "dark" or "static" when that assumption is true.  Over the centuries of the European Middle Ages or Ancient Egypt, everyone acted like their parents did, so nothing ever seemed to change except accidents of war and the name of the king or pharaoh.  Our transportation modeling assumes that ours is such an age.

Historical progress arises from people making different choices than their parents did, and there seems to be a lot of this happening now.  

What we urgently need, in this business, are predictions that try to quantify how the future is not like the past; for example, by studying Millennial behavior and preferences and exploring what can reasonably be asserted about a world in which Millennials are in their 50s and are in the position to define what is normal, just as their parents and grandparents do today.

We already know that the future is curved.  (With rare exceptions like the growth of VMT from 1970 to 2004, the past has been curvy as well).   Millennials are not like their parents were at the same age.  There will be major unpredictable shocks.  There are many possible valid predictions for such a future.  The one that we can be sure is wrong is the straight line.  

My work on Abundant Access – part of the emerging world of accessibility studies — is precisely about providing a different way to talk about transportation outcomes that people can believe in and care about.  It means carefully distinguishing facts from predictions, and valuing things that people have always cared about — like getting places on time and having the freedom to go many places — from human tastes that change more rapidly — such as preferences and attitudes about transit technologies. It's a Socratic process of gently challenging assumptions.  Ultimately, it's part of the emerging science of resilience thinking, extending that ecological metaphor to human societies.  It posits that while the future can't be predicted there are still ways of acting rightly in the face of the range of likely possibilities.  

Imagine planning without projections.  What would that look like?  How would we begin?

Transitmix: a new tool for armchair transit planners (and pros too?)

Screen Shot 2014-06-10 at 10.06.05 AM

Another interesting web transit app, this time from a group of Code for America developers:

Transitmix is a sketching tool for transit planners (both professional and armchair) to quickly design routes and share with the public. 

Transitmix is simple way to think about transit in terms of bus requirements and real costs. Basically, the user draws a route on a map and plugs in span and frequency. The app then calculates a vehicle requirement and cost in both hours and dollars, factoring in an adjustable layover ratio, average speed and dollar cost per service hour.  

Screen Shot 2014-06-10 at 10.06.13 AMScreen Shot 2014-06-10 at 10.06.17 AM








Transitmix is very similar to (though much simpler and prettier) the sort of cost estimation methods used in transit design processes , and as it stands is a fun sandbox to think about transit in your city. It's still very much a beta, but the prospects are intriguing. 

Its clear that the developers of Transitmix see it as much more than a curiosity. They've actively sought feedback from people in the industry, and are working hard to build an app that could one day replace some of the tedious documentation work of network design with an interactive, visually attractive interface. Apparently functions like summary tables, GIS file exports, and the ability to save multiple iterations of one design are all in the works.

I can imagine all sorts of possibilities for a tool like this, particularly if secondary data sources were incorporated. How about a public or stakeholder  involvement process that would actually give people a way to view demographic and ridership data and make real, financially constrained transit choices with a familiar, modern toolset? Or an update to our transit network design courses, where participants are given the same information for a fictional city and asked to design a transit network from the ground up? It's great to see transit concepts picked up by a talented group from an organization as reputable as Code for America. A project worth keeping an eye on!

email of the week: from a 10th grader, on streetcars

From Henry Mulvey, of Massachusetts:

Hello, my name is Henry Mulvey, I am a tenth grader. I am a huge streetcar fan and I love the old Boston Elevated Railway. I hope to attend M.I.T. for urban planning then work the M.B.T.A. or the state on a big replica streetcar plan for the city of Boston. I just read your article saying streetcar aren't what they seem and I have some rebuttal points.  I'm going try my hardest to be civil because I am a die-hard streetcar fan.  The two things I see that you either underestimate or don't mention are the aesthetic appeal of streetcars and the environmental costs of buses.  Streetcars look very different than buses and people like that.  In the case of replica streetcars, they might not carry as many passengers as modern types but they make people think "ooh, that's cool! I want to ride!".  Streetcars are more attractive than standard old buses, even an updated bus!  Streetcars are also more environmental friendly than buses.  Ideally streetcars do not omit any pollutants and are much more efficient than buses.  I also think the connection between streetcars and economic development is well documented and you don't provide any evidence to the contrary, can you give me evidence?  It's my belief that a streetcar line that uses replica streetcars does both provide great transit and showcases history.  Boston is a city that loves history and has a need for streetcars so I think a streetcar would work incredibly there.  Thank you for listening to me, Henry Mulvey

My reply:


Thanks so much for your note.  I love streetcars too, for all the reasons you mention.  
But all that beauty is expensive, and when we choose something more expensive, that means we can't afford as much of it.  That's a big problem for transit, because transit needs to be abundant.  It needs to go lots of places, so people can rely on it for lots of purposes.  That's why buses have to be respected, and have to be improved, because they're the only form of transit that we can afford to extend to all the parts of the city that need and justify good service.  Buses generate lots of real estate development too, although they're usually not given credit for it.
Yes, streetcars are driving some development right now, but that's also because lots of people are saying that streetcars drive development.  Streetcars are cool, in the same way that certain clothes are cool among people your age.  The real estate market is like your friends at school:  It wants to do what the "cool" people are doing. 
Fifty years ago streetcars weren't cool at all.  A decade from now they may not be so cool either,  My hometown, Portland, built streetcars mixed with traffic so that they run 6 mph and can't maintain a schedule.  Many of us find them useless if we're just trying to get where we're going on time.  [Because being late isn't cool, either.]    
And cities that have lived with streetcars for a while have mixed feelings about them.  For example, in Toronto they've kept their old streetcars and run them in mixed traffic, and you'll hear lots of frustration with them.  In fact, the mayor there is trying to kill light rail projects, and he does this by calling them "streetcars."  That's a dishonest description of light rail, but think about why he would say it:  He says it because knows that many people in his city hate their slow and unreliable downtown streetcars and don't want any more of them.  
As more new streetcars get built in mixed traffic, more and more people are going to figure out that if you're stuck in traffic, you'd rather be on a bus, because a bus can maneuver and often get through where a streetcar is stuck.  
I have very different feelings about "streetcars" that have their own lane, but I don't think of those as streetcars at all.  That's light rail, like the surface parts of your city's Green Line. 
Anyway, I've thought and written a great deal about this.  The piece that you probably read, because it gets the most attention, is this one, but these two are also important.
Thanks so much for writing to me.  It's great to hear about your interest in transit and your ambitions. When I was in 10th grade I knew my city's bus system by heart and hung around the transit agency's planning department after school. I was mostly a nuisance, probably, but I had just enough good ideas that they kept me around.  Don't be afraid to be so audacious, at the right time and place.
All the best, Jarrett 

guest post: vehicle automation and the future of transit

Antonio Loro is an urban planner with a particular interest in transportation innovations. In research conducted for TransLink and Metrolinx, he investigated the potential impacts of vehicle automation technologies. The views expressed in this article are those of the author and do not necessarily represent the views of, and should not be attributed to, TransLink or Metrolinx.

AnthonyLoroVehicle automation is increasingly showing up on the radar of urban planning and transportation planning professionals. Technologies are developing rapidly, and some news stories report that fully self-driving cars are just a few years away. It’s tempting to envision automation ushering in a bold new era in urban transportation, where driverless cars whisk passengers between destinations safely and conveniently, use roads with great efficiency, and make public transit as we know it obsolete.

However, a closer look at vehicle automation reveals a more nuanced picture of the future. Automation capable of replacing human drivers in any situation may be many years away from the market. The traffic flow improvements enabled by automation will be limited in several ways. Buses and other forms of public transit will still be needed to efficiently move large numbers of travelers around cities. And various forms of automation in buses could enable major improvements in service.

The last two points have come up on this blog before (here, here and here), but since there are a variety of opinions on the implications of automation for transit, it’s useful to dig a bit deeper into these issues and take a critical look at when various forms of automation will arrive, how automation will affect traffic flow, and how it will affect travel behaviour. This post will delve into those questions to shed a bit more light on what automation means for the future of public transit.

According to some, vehicles that can drive themselves anywhere, anytime, without any human intervention – described as “Level 4” vehicles by the National Highway Traffic Safety Administration (NHTSA) – are just around the corner. In 2012, Google co-founder Sergey Brin said of their famous self-driving car: “you can count on one hand the number of years until ordinary people can experience this.” Many others have made bullish predictions. For example, the market research firm ABI Research foresees Level 4 cars on the roads by around 2020, and panelists at the Society of Automotive Engineers (SAE) 2013 World Congress predicted arrival between 2020 and 2025.

On the other hand, some point to a number of challenges that suggest Level 4 will emerge further down the road, perhaps not for several decades. Steven Shladover of the California Partners for Advanced Transportation Technology, a leading expert on vehicle automation, argues that Level 4 will be much more technically difficult to achieve than many optimists acknowledge (see Vol. 7, No. 3 here). According to Shladover, huge advances in technology would be needed to progress to systems capable of driving safely in the vast range of complex and unpredictable situations that arise on roads. In addition, such systems would have to be far more reliable than products like laptops or mobile phones, and extensive – and expensive – testing will be needed to prove reliability. While Google’s vehicles have driven long distances in testing – over 500,000 miles as of late 2013 – and have not caused any crashes while in automated mode, Shladover points out that this proves very little because their vehicles are monitored by drivers who take over when risky or challenging situations arise.

Legal and liability issues could also delay the emergence of Level 4 vehicles. A few American jurisdictions now explicitly allow automated vehicles on public roads for testing, and Bryant Walker Smith, a leading authority on the legal dimensions of vehicle automation, has found that automated vehicles are “probably” legal in the US; however, he also cautions that their adoption may be slowed by current laws. Laws will have to be clarified before Level 4 vehicles hit the mass market in the US and in other countries. Liability for crashes could also be a thorny question. If a human isn’t driving, presumably blame would shift to the manufacturer, or perhaps a supplier of system components, or a computer programmer. Resolving these issues could stall the emergence of automation.

While there is dispute as to when Level 4 vehicles will be on the road, most in the field agree that more limited forms of automation are coming soon. Some are already here. For example, Mercedes S-Class vehicles can simultaneously control speed and steering when road and traffic conditions allow, though the driver must continuously monitor the road. This is just shy of “Level 2” automation, since Mercedes’ system also requires the driver to keep their hands on the wheel. Numerous other vehicle manufacturers are developing advanced technologies that promise to take over driving duties, at least some of the time, on some roads. As technologies advance, “Level 3” vehicles could be on the market by 2020 to 2025, according to most experts. These vehicles would allow drivers to forget about monitoring the road and instead read or watch a movie, with the caveat that when the automated system is out of its depth, it would ask the driver to take over. (The takeover time is a matter of debate – anywhere from several seconds to several minutes has been suggested.)

Automation could be a boon for safety – or it could create new problems. On the plus side, it appears that crash avoidance systems already on the market may be effective. Of course, as machines take over more of the responsibility of driving, safety will only improve if the machines are in fact less fallible than humans. This might seem an easy task, considering the foibles of humans, but it’s worth remembering that some automation experts believe otherwise. And where driving is shared between human and machine, the safety impacts are especially open to question. A driver in a Level 2 vehicle might fail to continuously monitor the road, or a driver in a Level 3 vehicle could be engrossed in their movie and fail to take over control quickly enough when requested. In either case, automation could actually decrease safety.

After safety, one of the biggest selling points of vehicle automation is its potential for improving traffic flow, especially through increased road capacity. With their slow reaction times, human drivers can’t safely follow other vehicles closely, so even at maximum capacity, around 90 percent of the length of a freeway lane is empty. If machines could react quickly enough, road capacity would increase enormously. Some studies appear to suggest huge increases are in fact possible – for example, one study estimates that capacity would almost quadruple, and another finds quintupled capacity. However, their calculations consider endless streams of densely-packed vehicles. More realistic estimates assume that several vehicles, say four to twenty, would follow each other in tightly packed groups or “platoons”, with each group separated from the next by a large gap. These interplatoon gaps would provide safety and allow vehicles to change lanes and enter and exit the freeway. Studies that account for these gaps estimate that automation would increase capacity in the range of 50 to 100 percent (for examples, see here and here).

While the more realistic estimates of capacity increases are still very impressive, there are a number of caveats. First, short headways are possible only when automated vehicles are equipped with V2V, or vehicle-to-vehicle communication. Vehicles that rely completely on on-board sensors – such as the Google self-driving car, in its current form – cannot react quickly enough to the movements of other vehicles, so they would enable relatively small capacity increases. A second caveat: large capacity increases would come only when automated cars dominate the road. Studies have found that when fewer than 30 to 40 percent of vehicles on the road are capable of platooning, there would be little effect on capacity, and large increases would come only after the proportion of equipped vehicles exceeds 60 to 85 percent (e.g., see here). This is important, since new vehicle technologies will take some time to become commonplace. Imagine that as soon as automated vehicles hit the market, every new vehicle purchased is automated: it would then take two decades for automated vehicles to account for around 90 percent of vehicles on the road. If the rate of adoption is more realistic, but still rapid, it would take three decades or more before automated vehicles make possible large road capacity increases. A third major caveat: platooning is only feasible on freeways. Changing lanes, stopping at red lights, making left turns, parallel parking, stopping for pedestrians – such manoeuvres would make platooning impractical on city streets.

For city streets, however, there is the prospect of using automation to improve flows at intersections by coordinating vehicle movements. A good example is the “reservation-based” intersection, where there are no stop lights or stop signs – instead, cars equipped with V2I (vehicle-to-infrastructure communications) technology “call ahead” to a roadside computer that orchestrates the movements of vehicles and assigns time and space slots for vehicles to cross the intersection. Simulations show such an intersection could move almost as much vehicle traffic as an overpass – but so far, simulations haven’t included pedestrians and cyclists. Accommodating these road users in a reservation-based intersection would require signals with sufficiently long cycles, so capacity increases would be limited.

Vehicle automation would also bring a very direct impact: reduced or eliminated labour in driving. Time spent traveling in Level 2 vehicles could be less stressful, and could become more productive and enjoyable in Level 3 and especially in Level 4 vehicles. Profound changes in travel behaviour would result. As people increasingly let their robot chauffeurs deal with road congestion and other hassles of driving, travel by motor vehicle would become more attractive. Trips would tend to be longer and more frequent and travel at peak times would increase. Trip routes would also tend to make greater use of freeways with Level 2 and 3 vehicles, since it is primarily on these roads that the vehicles will be able to operate in automated mode.

These induced demand effects would tend to increase road congestion. Freeways would be the exception – if platooning-capable technology becomes widespread, freeway capacity would increase and congestion would drop. That is, until the surplus capacity is taken up by the “triple convergence” of mode shifts, route changes, and change of time of day of travel. However, the increase in freeway traffic would be constrained by capacity limitations on the rest of the road network – as freeway travel increases, new bottlenecks would form on streets near freeway entrances and exits, where automation does not boost capacity, thus restricting the volume of traffic that can access the freeway.

The upshot of the above observations on the capacity effects of automation is that even when the potential freeway capacity increases enabled by platooning are fully realized, automated cars would nevertheless be able to carry far fewer people than bus or rail on a given right-of-way. And, as mentioned, capacities on streets will be largely unaffected. Because the capacity improvements made possible by automation would be limited, we will still need buses and trains when space is in short supply and we need to transport large numbers of people. Larger vehicles will still fit a lot more people into a given length and width of right-of-way than platoons of small vehicles will be able to carry. As Jarrett would say, it’s a simple fact of geometry.

So, vehicle automation will not render large transit vehicles obsolete. On the contrary, it could enable significant improvements in bus service and increases in ridership. Automated steering enables bus operation at speed in narrow busways, which reduces infrastructure and land costs. It also enables precise docking at passenger platforms, which improves passenger accessibility and reduces dwell times. Automated control of speed enables bus platooning, allowing buses to effectively act like trains. Automation can be taken further yet: a driver in a lead bus can lead a platoon of driverless buses, thus providing high capacity with low labour costs. Similarly, individual buses or platoons can operate driverlessly, thus enabling increased frequency with low labour costs. “Dual mode” operation is also possible: imagine a busway where chains of buses leave the city running like a train until they separate at a suburban station, where drivers board and take them onward onto various local routings.

Some of these forms of automation have already been implemented in BRT systems. For example, a system in Las Vegas employed optical sensors to enable precise docking at passenger platforms, BRT buses in Eugene, Oregon used magnetic guidance to facilitate precision docking and lane-keeping in a pilot project, and systems in Paris and Rouen, France, and in Eindhoven, the Netherlands, use various types of guidance systems. While bus platooning and driverless operation have not been deployed so far, these applications could be achieved given sufficient technological advances – or by using a low-tech shortcut. The simple solution is to keep other vehicles or humans out of the way of the automated bus. If buses operate on busways with adequate protection, platooning and driverless operation is possible with existing technology. (Similarly, current driverless train systems are able to operate driverlessly, even with decades-old technology, by virtue of the well-protected guideways they run on.) Developing a vehicle capable of driving itself in the simplified environment of a protected busway is a considerably easier task than developing a vehicle that can drive itself on any road, anytime.

With the arrival of Level 4 automation, driverless buses could operate on the general road network. This would make it possible to operate smaller buses at higher frequencies, since labour costs would no longer constrain frequency. If you shrink driverless buses small enough – and provide demand-responsive service for individual travelers – you end up with driverless taxis. This points to the possibility that public transit service may be more efficiently provided by driverless taxis (or driverless share taxis) in low-density areas, thereby replacing the most unproductive bus services and improving transit productivity overall. (Of course, while automation could boost productivity, even driverless demand-responsive service would still have low productivity where densities are low.)

While it’s a seductive story that driverless cars will transport us to a realm of much improved safety, convenience, and efficient road use – and where public transit has dwindled away – the future is likely to be more complicated. Advanced automation is indeed coming soon, though we might not see Level 4 technologies for a while. Automation could improve safety, though it could also generate new problems. It could also improve road capacity, but the improvements would be limited in several ways. All this suggests that we needn’t worry about (or celebrate) how vehicle automation will make public transit obsolete. Instead, let’s focus on how to use automation to the advantage of public transit. 

are smartphones changing the geography of our cities?

The increasing prevalence of mobile communications technologies has important consequences for urban transportation. The new ability to carry your social life around with you, enabling instant connections regardless of physical location, has the potential to reconfigure how we think about time and mobility, and in turn how we build environments to suit our travel behavior.   For example, it appears to be impossible to use smartphones safely while driving, so smartphone users have a motive to seek an alternative mode so that they can make use of their travel time.

 Ben Schulman has an interesting take on this in his paper, The Car as Smartphone: Effects on the Built Environment and Sociality, which you can download below. He places the smartphone in a continuity of change in human communications technology, and traces how those technologies have helped to shape our cities. 

The built environment then is a reflection of the predominant communication devices being used at given points in time that shape sociality. In other words, we develop an infrastructure necessary to accommodate the needs of our preferred communication tools.

This idea is a larger envelope around the familiar idea that all cities are built around the transportation technologies of the time.  Transportation, after all, is one kind of communication tool.

There is a lot of to digest here, but it is well worth a read in order to situate these trends within an academic urbanist frame of reference. My take is that the role of communication is hugely important, but must be understood as an aspect of a broader web of economic and social relationships which together work to produce the space of the city. 

Download Schulman—car-as-smartphone-2

why are americans driving less? better communication options!

Over the last 15 years, the Internet and mobile communications technologies have transformed the way Americans live and work. During that same period, growth in [motor] vehicle travel slowed and then stopped, with Americans today driving about as much on average as we did in 1996.

USPIRG has a new report out today, focused on how network technology has ushered in new possibilities for Americans’ personal mobility. Modern communications are beginning to alter the types of trips people need to make, as more and more people work remotely for at least a portion of their working hours. The mobile, high-speed, GPS devices that a majority now own are absolutely necessary to the cellphone trip planners and various -sharing systems that have spread to many US cities in recent years. 

This is one of the most compelling arguments for why we should expect America’s declining interest in cars to be permanent.  

The “decline of cars” story is a hard one to convey to the currently ruling generation (now in their 40s-70s).  Older folks too easily assume that Millennial disinterest in cars has something to do with being young and single and childless and maybe poor.  

We already knew that Americans are getting drivers licenses later and later in life — and this statistic ought to get attention because it’s comparing Millennial behavior to that of their parents at the same age.  

The strongest story, though, presents not just a trend but an explanation of it, and that’s what we have here.  Communications technology explains why the younger generation is finding cars less necessary (and why older people who are good at technological uptake are finding the same thing).  People still need to be together (see Yahoo’s recent decision to abolish telecommuting) but communication technology is replacing a lot of errands that the older generation is used to doing with cars.

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USPIRG reviews a broad array of recent research on the topic, concluding:

By providing more
choices and flexibility for individuals to meet their transportation needs,
these new tools can make it convenient to adopt “carfree” and “car-light”

Households that reduce
the number of vehicles they own often dramatically reduce the number of miles
they drive. Because many of the costs of owning a car are perceived to be
fixed, vehicle owners perceive the cost of driving an additional mile to be
artificially low. New services such as carsharing shift the cost of driving
from fixed to per-mile costs, providing an incentive for users to drive less
and allowing many households to reduce their overall spending on

Information technologies make it easier to ensure seamless connections between various modes of transportation, expanding the number and types of trips that can be
completed effectively without a car.

The report also discusses mobile ticketing, perception of travel time, and each of the various sorts of sharing services, and provides a set of policy recommendations to respond to and build upon the potential of this technology. Read it yourself here.