> If you are going to geofence self-driving cars it's questionable whether they are better than trains and buses
They run on demand 24/7, they run point to point, you never have to stand, you don't have to share the space with people who behave antisocially, you have a range of choice of comfort options, there are unlimited competitors for the same route driving prices down and service standards up.
So, quite a few game changers for me at least.
If you live/work outside the geofence, this obviously doesn't apply, but if you do then you get the advantages 80% of the time, and for day to day purposes it absolutely is fundamentally better than trains and buses.
I'm first in line to agree with you, I think cars in cities are awful because of these two problems, and honestly I support all sensible efforts to reduce the number of (current generation) cars on city streets.
I'm also a daily user of public transport in a major world city, however, and whilst buses and trains work they also have the fundamental problems highlighted above that are in my view insurmountable, and which (self driving) cars solve. So I'm in a dilemma over whether I think they'd be an improvement, but I ultimately believe they would be.
But yes, absolutely pollution and space saving would have to be addressed. I'm optimistic they could be:
Pollution: hopefully solvable with electric. Yes, of course, there are efficiency gains that trains/buses would perhaps always have (having to move many small things rather than one big thing carrying the same number of people) but I can see electric reducing the absolute level of pollution from cars to a point where it basically doesn't matter. Maybe overly optimistic, but I hope that'll happen.
Space: Driverless cars, particularly electric driverless cars, can be much smaller and can drive much closer together. Different cities have different challenges, but I don't see why we couldn't get to a situation where roads might effectively have capacity for 2x vehicles across and 2-3x vehicles along if the vehicles can be coordinated to drive closer together and are physically smaller (remember that on-demand unlocks certain design constraints - you don't have to provision for peak - if the average number of passengers is 1.5, then most cars on the road could be ultra small 2 seaters). Again lots of conjecture and optimism here, and I am probably assuming that 'manual' cars would eventually disappear or be banned at least from cities too, but nonetheless I think there is hope here.
Public transport will always be able to pack more people into the same space.
There is a minimum amount of space occupied by the vehicle's own matter. The ratio of that material to the occupant is a scaling law: the larger the vehicle, the higher the volume-to-surface, the denser the passenger-to-vehicle ratio can be.
A standard R160 subway car carries up to about 250 people in an area that would be about the same as 5 Corollas positioned nose to tail, a starting ratio of about 10:1. If cars are made twice as dense, it's still 5:1.
This is ordinary batching. The only thing that can carry more people more densely than a bus or train is the footpath.
> Public transport will always be able to pack more people into the same space.
While that's true, that's also just an argument for something we already understand. Are there possible arguments to be made about the number of busses and routes because it's not taking people point to point. What about the lul-time of day, where on-demand model is more efficient than driving empty busses around. They reduce schedules obviously. But now you're punishing passengers that start a shift at noon. There are more things to solve than just "the least amount of pollution and space."
Totally unrelated but similar argument. The FAA introduced a new system and process for creating standard flight paths a few years ago. Flights around the nation started doing new things. TONS of people are now inundated by jet noise. They're now discussing just going back in certain areas to the old routes. They ONLY optimized for efficiency of route and didn't consider anything else.
> There are more things to solve than just "the least amount of pollution and space."
The argument I was responding to was that self-driving cars would be sufficiently more efficient users of space that it would obviate the need for public transport. This was demonstrably false.
> But now you're punishing passengers that start a shift at noon.
Sure, but (a) that's a financial question, not a capacity question and (b) rush hour is when both finance and capacity collide.
Public transport is a more efficient option per passenger-kilometre and per square metre of road or cubic metre of tunnel than self-driving cars. It is always going to be. Self-driving cars will have other virtues and will reshape transportation, but ascribing magical powers to them does nobody any good, especially if it leads to defunding of subways and buses.
Yes you're absolutely correct - I guess my main question is could the space savings, like the pollution savings, be 'good enough' for it not to matter in practice, assuming that driverless cars become the 80% usecase for road traffic and today's 'massive 5 seater car for an average of 2 people' model goes away.
It's also important to point out that of course, buses and trains shouldn't go away - they could indeed also have a bunch of problems solved by being self driving too, most notably the 24/7 running thing - they'd just be another option in the mix.
>A standard R160 subway car carries up to about 250 people in an area that would be about the same as 5 Corollas positioned nose to tail, a starting ratio of about 10:1. If cars are made twice as dense, it's still 5:1.
You're not accounting for the space between trains. They will only take up 5-10% of the available rail space because you need gaps between the trains.
You need gaps between cars, too. Two seconds of following distance in good weather conditions, four seconds of following distance in bad weather conditions.
At highway speeds, 4 seconds of following distance is 120 meters.
> You're not accounting for the space between trains.
NYC's least efficient system is block train control, requiring 300M separation between trains.
In 300M you can fit about 66 Corollas, again packed bumper to bumper. That's 66 * 5 people = 330 people, or approximately 1.5 subway cars.
Subway trains are 6 or 8 subway cars long, depending on track and time of day.
With CTBC some platforms can run at 60 trains per hour (30 local, 30 express). That's 8 subway cars every 2 minutes, or approximately 1,000 people per minute.
To move 1,000 people at all with the Corollas you will need 250 * 4.55M of them, or approximately 1.1 kilometres of cars, bumper to bumper.
>With CTBC some platforms can run at 60 trains per hour (30 local, 30 express). That's 8 subway cars every 2 minutes, or approximately 1,000 people per minute.
Unless your trains are going at 10 kph you will have more of a gap than 300 meters if you see a train every 2 minutes.
But you're always limited by loading time. If you take X seconds at each stop then you will end up with X * speed distance between each car. Even at 30s loading and 50 kph you're looking at 400 meters between each train.
Packing more self-driving cars onto roads is an appealing notion, but I don't think it holds up to scrutiny. Even if a computer detects hazards instantly and continuously negotiates with and anticipates the movement of other vehicles, the physics of moving cars remain the same. Safe stopping distances won't be dramatically different. Road surfaces, stray animals, mechanical failures, and any number of other hazards don't care who or what is driving a car.
Say you have 3 lanes of traffic. Each lane is occupied by 100% driverless cars.
Let's say, there is an object completely blocking the middle lane, and partially blocking the two outer lanes. What will the driverless cars decide to do?
My guess, is they wait there until the road is completely unblocked, there's no way for the cars to understand the proper course of action. It will be great fun to bring absolute gridlock with an empty cardboard box in downtown NYC once this all kicks off. Naturally, by then, card board will be illegal there.
Why would driverless cars be smaller? They still need to be able to carry the same number of passengers; the only difference there is that one of those passengers is no longer also a driver.
With autonomous cars, robotaxis become feasible. If you're buying a car for yourself, you're going to want a certain amount of space for passengers or cargo in case you need to do something like drive your family to the airport. You'll also want long range in case you decide to go on a road trip. Even if 90% of the time you'll be commuting alone 20 minutes to work, you'll want this extra range and capacity for the times you need it.
If you're deploying a fleet of robotaxis, most of your fleet can be vehicles that only carry one or two passengers at a time on short trips. If a family wants a ride to the airport, then they'll specify that they need a larger vehicle for more passengers and luggage, etc. So you can buy a fleet of mostly smaller cars with a shorter range, and compliment them with a few minivans for long range trips. Overall your fleet will be quite efficient.
Yep, and given that some big percentage of car seats are not properly installed, do you then have to take the requisite minutes to install and uninstall each seat properly? There are a lot of challenging edge cases.
I've been on double-length public buses where I was the only passenger for most of the journey. And many times where there were only 1 or 2 other people. This is necessary e.g. at night where a bus only runs every 30 minutes, there has to be a bus, but there just aren't that many people.
Obviously in this case individual cars would pollute much less, and even take up less space.
Any realistic solution for a city is going to combine self-driving cars for the long tail of origins/destinations and times, with public transit for the busiest routes at the busiest times, including links between the two.
I'd love to be able to take a self-driving car from a house in Queens directly to the subway, the subway to Brooklyn, and then another self-driving car to my final destination that's 20 blocks away from the subway.
On average public transit produces 2% of pollution but transport about 28% of riders. (I don't remember where exactly I got the numbers but I've seen them in a few places).
The buses need to run at night so the people can rely on them during the day -- it's just the price of public transit, the public uses transit way more if buses run on 10-minute interval during off-peak rather than 30-minut interval. (another study I can't find right now).
I think as programmers we tend to try and optimize problem for least pollution, but the problem here lies in the domains of sociology and urban planning; we might not be the most qualified people to solve it.
For example if buses pollute 3% because of the extra buses on off-peak routes but now more people use them, this would have net effect of reducing pollution.
Was going to downvote but this probably merits a reply.
All your points are correct, but you're not responding to the point that SDCs can be superior to buses for those low-capacity times. If it were one or the other, then yes, buses could be less pollution on average, but that doesn't address the case the parent was talking about.
Prior to low cost ride sharing, a good bus system that people will use as an alternative to cars pollutes more because it has to run a lot mostly empty buses to satisfy long tail demand.
To the extend low cost ride sharing is a short term unicorn phenomena, that will again become true, although self-contained electric buses might change that a bit. Maybe someday self-driving cars will change this, but that's not in the predictable, foreseeable future.
Yeah this is the really interesting part - like where does the 'supply provisioned precisely to match demand' thing for self driving cars meet the 'buses/trains are more efficient assuming some % capacity filled', how does that relate to demand changing with hours of the day, where people live, etc.
It's just a fascinating optimisation problem. I think the answer is far from clear, and certainly couldn't be reliably approximated without lots of real world data.
Also if you live for a part inside the geofence, You can give full AI autonomy inside the geofence and take over outside. This would be especially useful when you have to travel long distances on the highway.
I totally agree, and they can take care of the last mile problem for trains at both ends, making trains more practical.
And GP said, "If the solution is flawed even a little bit, people will die." Well, yes, and if humans drive, people will die.
If the flawed machines reach the point where they are provably statistically better than the flawed people who currently drive, lawsuits claiming that people who choose to drive and get in accidents are negligent will cause insurance companies to jack up the rates on "self-drivers".
That's where the state-change sigmoid curve will suddenly turn upward.
Yeah, this is something that really bugs me about public transport.
It's simply not acceptable to have to stand on a bus. Ever. It should be treated as some sort of breakdown/failure condition. If it happens on more than a few % of journeys, the public transport authority should be putting on more buses.
Otherwise people are just going to take their car because they actually have control over their own comfort.
With trains it's a little harder due to physical constraints on the network, but with buses it's inexcusable to not just have more capacity, particularly at peak time (London buses get silly in the morning peak, for example).
edit: Replies here are completely missing the point. A car has comfortable seats whenever you want them. It's honestly a comical joke to have to explain "why I don't want to stand up". The obvious answer is because I don't have to in my car.
Public transport can be, and should be as comfortable as that. It can't be as private, sure, but there's no need for it to feel like cattle class.
I'd gladly pay twice as much for it to be better. It easily could be; in London for example if everyone gave up their cars and put the money towards public transport we could double or triple the number of buses.
Also, wishing for a blanket increase in total number of busses by some huge percentage to avoid anyone standing probably sounds like a real nice plan until you have to pay for it... Capacity management isn't as easy as throwing drivers and busses at the problem.
Will they? When I drive I have to worry about parking and, you know, driving. If I take a taxi or ride share I'm paying on the order of 6x what the bus costs.
I think you're overstating the annoyance of standing on a bus.
> I'd gladly pay twice as much for it to be better.
Some other comments mentioned classism, and anti-social passengers, but a less emotionally charged way of framing it is just in terms of price discrimination.
Busses and subways have no "first class" or "business class" section. The passengers who would pay double or triple are doing so in their car payments, insurance, and gasoline, and riding in relative comfort, and the people left riding the bus are mostly those who aren't willing to pay more.
It's going to be difficult to get people to put their car payments toward better bussing, while still keeping it accessible to those who want to pay less.
> Busses and subways have no "first class" or "business class" section.
It depends. New York City has "express buses" that are basically long-distance buses repurposed for commuting. You pay an additional fare and are more comfortable. Commuter trains are of course more comfortable than subway trains. (This is why I usually fly out of JFK. Taking LIRR to the airport is much nicer than taking the bus to LGA.)
Japan's rail systems have higher-tier options on some route. JR has "home liners" that are long-distance passenger trains basically repurposed for commuters (actually very similar to the default commuter train in the US, whereas the normal commuter trains are very similar to metros). Tobu has the "TJ Liner" which is similar. The demand does exist.
I think the reality is that public transportation is too popular to reduce capacity by having more seating. Everyone in NYC would pay for a more comfortable subway, but there wouldn't be enough trains to carry them all. The completely-packed-at-rush-hour is a byproduct of the fact that cars just aren't faster in NYC, so you might as well pay $2.50 to get home faster but in less comfort. (I've looked into it. There were many times when I was running late and thought, "maybe I'll just take an Uber to work today". But the delayed subway would take 20 minutes and the private car would take 30 because of traffic. It only made a difference in the middle of the night when the subway was running on 30 minute headways and there was no traffic. Even then, still close to 20 minutes to drive. The subway is just that efficient, despite everyone's complaints.)
Yeah I think this is the main challenge - you can have private buses are that are comfortable and provide a net positive over driving yourself. These exist in the bay area (FB, Google, Apple all do this) but then they're not public transport.
Right, which is why public transport should be funded via taxation.
The way to achieve a reasonable service is actually to tax driving at a higher rate (to account for the externalities; pollution, congestion etc) and put the funds into infrastructure like buses/trains.
I often drive because it's more efficient and comfortable than using the bus. It's more efficient and comfortable than using the bus because the externalities are not priced in.
We can address that balance by taxing cars higher and putting on more buses / paying for more cleaners, etc.
Really depends on the distance and the rides harshness, that's why we have buses and carriages filled with people who didn't take a car anyway.
Definitely not ideal but we can't optimize just for one thing. Putting more busses on demand has really hard scaling problems because of these busses don't appear and disappear like a virtual machine, it needs to be stored somewhere and delivered to the location where that bus is needed. Then you have load-unload problems. This is also why cars that are just like the cars of today but electrical and automatical won't scale too.
You can't really divorce the design of the inhabited areas and the transport systems. This is also probably the reason why the Americans seem so hostile towards public transport. In Europe and even in Asia public transport works fine and the most annoying thing about cars is not that you have to drive them but you have to put them somewhere when you reach your destination.
> If it happens on more than a few % of journeys, the public transport authority should be putting on more buses.
That's unrealistic, because there are such huge peaks in traffic. You'd need a large number of extra bus drivers only from 7:30 to 8:30 and from 17:00 to 18:00 each day.
"such a job" would not be made available as bus drivers are typically unionized employees and that is one reason part-time bus driver positions do not exist
I take the bus and I'm neither poor, nor a particularly good environmentalist. They're convenient and cheap and I sorta prefer it to putting my life in the hands of a sleep deprived wage slave. Uber rides feel _consistently unsafe_ to the point I don't even consider it an option anymore.
IME most of the resistance people have to taking the bus is classism. They don't want to share space with "those people".
Presumably then, in your area, buses are superior.
This is exactly what I am talking about. They are not everywhere, and they should be.
I prefer buses too when they actually work.
I tend to take public transport a lot more off peak. At peak time I vastly prefer cycling or driving depending on the weather because I find being crammed next to other people disgusting (a failure mode unique to public transport).
It’s not about class at all. It’s that people don’t want to share space every day for an hour each way with loud people, smelly people, crazy people, violent people, etc. And if they do, they sure as hell don’t want to do so standing and packed up against them. Not all cities and routes have these problems, but many do.
Nobody objects to having to share space with a broke working class single mother taking the bus to go clean hotels downtown.
Aside from that, the weather can be a pain in the ass (rain, snow, wind, scorching heat), transferring buses/trains is a hassle, you cannot travel on your own scheduling terms, you can’t swing by the grocery store or run some errand on the way home, travel time is generally much longer unless you happen to live/work right beside an express stop that does not require a transfer, and the list goes on.
Or... cities see self-driving cars, draw the correct conclusion that they can put some smaller, cheaper and more efficient self-driving buses and blanket ban cars in places where there are too much of them. You either walk or take the bus.
Ok, but check this out: self-driving buses! It's easier to make a self-driving vehicle that follows a fixed route. Buy enough buses to cover the peak demand, then send most of them back to garage during non-peak times.
It's solvable, especially since it's the government that is responsible for public transportation. For example, you can arrange another job for the non-needed hours. For example - a taxi driver.
> It's simply not acceptable to have to stand on a bus.
you need bus fares to cost less than car travel or people'd just drive everywhere and car ownership/congestion comes with it's own set of issues.
it's annoying but having enough capacity to handle peak hours would also see lot more buses parked off hours, lot more technicians doing maintenance.
given the seated:standing capacity on current models, you'd end up with twice to thrice the buses to seat everyone.
now this wouldn't immediately mean to have triple the fares, but it'd be a significant factor and limit/reduce total bus usage, and there's no indication the consequences for society would actually be net positive compared to standing.
> Otherwise people are just going to take their car because they actually have control over their own comfort.
The fact that many people don't indicates there are other factors at play.
I bet there's a diminishing return to this. The more buses you add at rush hour the more traffic you cause and thus slow things down reducing capacity. In heavy traffic buses tend to clump together as they get stuck behind one another due to the nature of smaller vehicles around them.
Also, what would be an acceptable cost increase to pay for this additional capacity? You'd have to balance the theoretical increase in ridership against the decrease from raising prices. Keep in mind that public transport is usually heavily subsidized, in the US its on average 50%.
Nope. In my location trams are new and clean. I just prefer to lean against the windows and people who need it more can use it. I don't travel more than 20mins with public transport, though.
Well, when I was working in the City and living in south London I used to take the DLR (which is a self driving train btw) and walk for 10min.
I can confirm that there were drivers on the streets as well as cyclist, pedestrians, bus riders, tube riders and so on.
All of those at their limits at rush hour. Later the city banned private vehicles from certain locations at rush hour, so you can do such changes to favour one transportation method over the othet but it's far from solving it. It's a very hard problem, very unlikely to be solved without redesigning the city.
The cost floor of driving even with automation is above the cost of public transportation in most cases. Because of traffic, the service standard will never approach public transportation in dense areas
They run on demand 24/7, they run point to point, you never have to stand, you don't have to share the space with people who behave antisocially, you have a range of choice of comfort options, there are unlimited competitors for the same route driving prices down and service standards up.
So, quite a few game changers for me at least.
If you live/work outside the geofence, this obviously doesn't apply, but if you do then you get the advantages 80% of the time, and for day to day purposes it absolutely is fundamentally better than trains and buses.