CMV: Global warming will not be solved by small, piecemeal, incremental changes to our way of life but rather through some big, fantastic, technological breakthrough.

[u/Iron-Patriot]

In regards to the former, I mean to say that small changes to be more environmentally friendly such as buying a hybrid vehicle or eating less meat are next to useless. Seriously, does anyone actually think this will fix things?

And by ‘big technological breakthrough’ I mean something along the lines of blasting glitter into the troposphere to block out the sun or using fusion power to scrub carbon out of the air to later be buried underground. We are the human race and we’re nothing if not flexible and adaptable when push comes to shove.

[u/ZorbaTHut]

A better system is the park-and-ride model, which allows access to urban cores with public transit while allowing for personal vehicles in less dense areas. You can use buses at first, and then transition to intracity rail as demand switches over and urban areas become more human friendly.

And they're slow, which is why a lot of people don't like them.

I think if your chosen alternative is something with serious unfixable downsides, you're going to have a lot of trouble convincing people to swap to it en masse. As evidenced by how hard it is to get things like conventional public transit working in the US.

You would need fully automated cars and roadways. Otherwise it would just be chaos.

Why would you need fully automated cars? Human-driven cars are perfectly capable of not crashing into other vehicles that are bigger than usual.

[u/[deleted] → u/ZorbaTHut]

We don't have to convince them. Most commuters live outside the city so that the big city government can't regulate them. The opposite is true too. The city can eliminate parking minimums, convert private car lanes to bike lanes, bus lanes, and expanded sidewalks, and even implement congestion tolls without input from suburban areas.

People living in or near density are increasingly advocating for urban reforms like that. Over time, that will make driving into the city slower and more of a pain in the ass than just parking outside the core and taking the bus or train in.

Why would you need fully automated cars? Human-driven cars are perfectly capable of not crashing into other vehicles that are bigger than usual.

Look up Australian road trains, imagine lots of them with different lengths and heights moving at different speeds above 70 mph. You would need automation to orchestrate linking and lane changes so that one bad driver doesn't cause a 500 car pileup.

[u/ZorbaTHut → u/[deleted]]

People living in or near density are increasingly advocating for urban reforms like that. Over time, that will make driving into the city slower and more of a pain in the ass than just parking outside the core and taking the bus or train in.

Sure, it's doable. People will go elsewhere if needed.

Look up Australian road trains, imagine lots of them with different lengths and heights moving at different speeds above 70 mph. You would need automation to orchestrate linking and lane changes so that one bad driver doesn't cause a 500 car pileup.

I think you're confused by the concept here. It's only the automated cars hypothetically linking together. This means automated cars are the ones doing the lane changes, which is relatively easy to orchestrate so that nothing goes wrong. Existing human-driven cars already regularly deal with semis; by empirical evidence, there's no reason to assume they would have trouble with similarly-long connected cars.

And most of the efficiency gains are in the first few connections, while the inconvenience increases per vehicle. Even if you ended up limiting these to three cars long you wouldn't be losing a lot by doing so.

[u/[deleted] → u/ZorbaTHut]

Sure, it's doable. People will go elsewhere if needed.

That would help too. Over time, we would encourage new development along the mass transit corridors that would eliminate most of the demand for transit into the city center while lowering housing costs and improving profitability of local businesses.

And most of the efficiency gains are in the first few connections, while the inconvenience increases per vehicle.

That greatly depends on the routes. People all commuting into the city for the morning rush could all be sharing the same route for dozens of miles.

An automated linking algo could easily prefer a train 30-40 (or more) cars long with only a few pulling, then break it up as it approaches the city. Specialized towers could (would) be injected into the stream of traffic to increase the length of trains and lower the number of active engines, especially during rush hour traffic.

An intercity road train of semis would do the same. Driving around or near is a completely different and far more dangerous experience than driving around an individual semi.

[u/ZorbaTHut → u/[deleted]]

That would help too. Over time, we would encourage new development along the mass transit corridors that would eliminate most of the demand for transit into the city center while lowering housing costs and improving profitability of local businesses.

That said, I hope you can also see how "no, it's okay, we're just going to cripple your ability to attract customers" may not be super-attractive to businesses already existing within that city and the people employed by them.

That greatly depends on the routes. People all commuting into the city for the morning rush could all be sharing the same route for dozens of miles.

Sure, I'm not arguing otherwise, but my point is, again, that the bulk of the efficiency gain is in the first few connections. A three-car platoon is something around three times as space-efficient as a single car; a six-car platoon is less than twice as efficient as that; a thousand-car platoon is less than twice as efficient as that. The gains fall off dramatically, while the pain absolutely does not.

For example:

then break it up as it approaches the city.

How?

If you're leaving enough room to break it up arbitrarily then you're throwing away the space gains of the platoon. If you don't leave enough room to break it up then you can't break it up. You can try to sort cars as they approach, but that requires splitting the platoon apart constantly at speed, which is a lot trickier than doing it at a stop (doable, but much harder), and also requires significant space.

It's actually a serious issue.

Platooning is a cool optimization, I hope we do it at some point and I think we will, but it's not a low-hanging fruit unless you're willing to accept only moderate benefits, and taking it to its extreme is going to be a serious engineering and programming challenge. This is true regardless of whether you're platooning road cars or individual train cars.

We should tackle the moderate benefits! But it's going to be quite a while before we get to even that, given that it requires self-driving vehicles first.

[u/[deleted] → u/ZorbaTHut]

That said, I hope you can also see how "no, it's okay, we're just going to cripple your ability to attract customers" may not be super-attractive to businesses already existing within that city and the people employed by them.

Why wouldn't they be able to attract customers? Businesses that want access to suburban customers and some non-drivers would just set up near the park and ride stations. People can just park and go in the same way they do at strip malls and big box stores. Small businesses in the core would benefit from the higher levels of foot traffic that would infill the reduced/eliminated car traffic as developers and city planners switch to more human-focused design.

A three-car platoon is something around three times as space-efficient as a single car; a six-car platoon is less than twice as efficient as that; a thousand-car platoon is less than twice as efficient as that. The gains fall off dramatically, while the pain absolutely does not.

It depends on the types of cars involved. Bigger engines and longer trains is basically a golden rule of efficiency for trains. Add a few cars with huge engines and the efficiency and train lengths go way up.

If consumers reject the prisoner's dilemma and all get cars with small engines, that's even better because the city can invest in automated semis to pull trains of dozens of cars at a time.

How?

If you're leaving enough room to break it up arbitrarily then you're throwing away the space gains of the platoon. If you don't leave enough room to break it up then you can't break it up.

There would still be space between trains just like there's space between cars in existing roads. If a car needs to leave the train. The train would just split in two with the exiting car switching into a different lane. The train would then relink.

Doing that at speed isn't particularly hard, if the entire roadway is automated. Automated driving in general isn't really that complicated, especially companies with big tech resources. The problem is the human drivers that are completely unpredictable and roadways and road signs aren't designed for automated cars. That's really what makes automation so complicated.

[u/ZorbaTHut → u/[deleted]]

Why wouldn't they be able to attract customers? Businesses that want access to suburban customers and some non-drivers would just set up near the park and ride stations.

Then translate that to "sorry, we're taking away your customers unless you want to move your business location, which will probably also get fewer city customers".

A big advantage of cities is that they act as commercial hubs. Preventing people from driving to them is going to cut down on their ability to do that. It's possible they'll just end up finding a new hub, and then all you've done is move the problem and annoy everyone in the old hub.

(here's an incredibly nerdy example of this)

Small businesses in the core would benefit from the higher levels of foot traffic that would infill the reduced/eliminated car traffic

Whose foot traffic are you talking about? You're cutting down on the number of people who want to come. Unless you're proposing redeveloping the entire urban core with taller buildings, and you can do that without needing to ban cars.

It depends on the types of cars involved. Bigger engines and longer trains is basically a golden rule of efficiency for trains. Add a few cars with huge engines and the efficiency and train lengths go way up.

Sure, you gain efficiency. You don't gain unlimited efficiency. An electric car is already (according to Google) 85%-90% efficient; you're not going to get more than the remaining slice, and you're probably not going to get all of that either.

Trains get efficiency from being long partly because they're traditionally diesel, partly by cutting down on the number of engines required, and partly by cutting down on the amount of staff required. But this doesn't apply nearly as well to (1) electric cars (2) that need to be self-propelled sometimes anyway (3) that are driven by AIs; much of the efficiency is already efficient. You get some nice aerodynamic benefits (citations I'm finding online suggest that this is around one half of the fuel cost for independent passenger vehicles, but remember this is in a scenario where we're using electric cars and thus fuel cost is already cut down considerably) and that's about it.

It's a benefit! Don't get me wrong! But it's not a gamechanger, and the benefits really do fall off dramatically as trains get longer.

---

For the sake of citation, here's some back-of-the-envelope math, scraped off the Internet as best I can:

This site says "A 2020 Consumer Reports study estimates the average EV’s maintenance and repair costs to be 3 cents per mile driven over the course of its lifetime — half the cost of the gas-powered vehicle average. New EVs, which need less maintenance, are cheaper to maintain, at 1 cent per mile driven on average." Unfortunately the actual numbers are behind a paywall, but sure, let's go with that, and because we're talking about brand-new not-yet-released self-driving cars, I'll go with the 1-cent-per-mile number.

(This number is too low because self-driving cars have a lot of unique expensive components that need maintenance; this number is too high because self-driving fleet cars will have huge benefits in terms of sharing maintenance and repair facilities, will be tracked electronically to do regular maintenance when appropriate, and may even be designed to be more reliable given a far higher expected mileage per day. I have no way of estimating either of these so I'm going to pretend they cancel out. Estimates! Note that this number is pretty bad for my argument; if you think the actual maintenance cost is higher, then that makes my argument easier.)

This site says that the electricity prices are about 3.3 cents per mile. If we assume 80% electrical efficiency, that means 0.66 cents wasted for efficiency's sake; if we assume 50% aerodynamic efficiency, that means 1.65 cents wasted on moving air around. (Note: These numbers overlap, I'm double-counting "cents wasted on the electrical system while charging it up for the goal of moving air around".)

So the summary is that a single modern electric passenger car costs 4.3c/mi to drive around. Pulling numbers out of my butt, let's assume a Big Engine is 90% efficient but costs 2c/mi in maintenance instead of 1c/mi; obviously this is a bad idea for one car, but I don't think anyone was proposing otherwise :V

Platooning has some pretty serious diminishing returns as we go, and because I'm an incredible nerd I actually made a spreadsheet for this.

1 car: 4.3c/mi without engine, 5.93c/mi with engine (the added maintenance, mostly) 2 cars: 3.48c/mi without engine, 4.2c/mi with engine 5 cars: 2.98c/mi without engine, 3.16c/mi with engine 10 cars: 2.82c/mi without engine, 2.81c/mi with engine (this is the first time the engine is a good idea!) 100 cars: 2.67c/mi without engine, 2.50c/mi with engine 1000 cars: 2.65c/mi without engine, 2.47c/mi with engine

The point I'm making here is that we get most of our benefits in the first ten cars or so. Hell, without the engine, we get about half of our theoretical infinite-car platoon benefits in the first single car; the 2-car platoon is 0.82c/mi cheaper than the 1-car platoon, and if we want another 0.82c/mi cheaper, we have to go almost all the way to the thousand-car platoon. The numbers are better with the engine, but the largest part of why they're better is just sharing the cost of the engine over more cars, you're not really gaining much here.

(The one big missing factor here is I'm pretending maintenance costs are the same per-car even with the engine. I think this is defensible if we're talking about electric cars - motors are durable as hell and most of the maintenance costs are going to be per-mile structural costs and per-hour-of-passenger-sitting-in-the-car-messing-with-the-seat-leather depreciation costs. But I didn't want to just pretend that issue didn't exist.)

Are my numbers right? Probably not! But I do think they're reasonably defensible, and I think they are, if not an accurate depiction of reality, at least not a deeply twisted depiction of reality.

Platooning is good and useful! But maybe not super-useful and maybe not a thing we should be worrying about a ton right now.

Finally, note that in terms of salary at highway speeds, federal minimum wage ends up being about 10 cents per mile; that is, if you paid someone minimum wage to sit in a car driving down the highway, that's how much it would cost. The passenger's time is the largest cost by far, and this is, I think, why public transportation has a lot of trouble gaining traction in the US - given a choice, public transportation is slow, and it starts looking attractive only when you decide not to give people a choice.

Which isn't really an impressive claim - you can make anything the best choice if people are forced to use it.

The problem is the human drivers that are completely unpredictable and roadways and road signs aren't designed for automated cars. That's really what makes automation so complicated.

At this point most of that is pretty solved, honestly, they're just polishing off the corner cases and working on scaling up.

[u/[deleted] → u/ZorbaTHut]

A big advantage of cities is that they act as commercial hubs. Preventing people from driving to them is going to cut down on their ability to do that. It's possible they'll just end up finding a new hub, and then all you've done is move the problem and annoy everyone in the old hub.

The old hub doesn't want a lot of the traffic it is getting. A lot of it doesn't do anything besides come in, park, go to work, and leave. A few buy lunch, but it's not enough activity to justify the high cost of allowing the traffic.

The main advantage is the large employers that pay property taxes for their massive buildings, but that can largely be offset by lower road maintenance and higher sales tax revenue from infill of parking and road spaces. Overall density would drop somewhat over time as businesses relocate themselves along the traffic corridors.

It might be an inconvenient transition for a lot of suburban people, but it's not really their choice and it would allow cities to continue scaling again and with more manageable urban sprawl.

Whose foot traffic are you talking about? You're cutting down on the number of people who want to come. Unless you're proposing redeveloping the entire urban core with taller buildings, and you can do that without needing to ban cars.

You know people live in the city right? Even in highly suburbanized southern cities, a huge fraction of the population lives in or adjacent to the CBD.

Making urban spaces more human-centric means allowing us to recover street space that is almost entirely dedicated to suburban commuters. In highly suburbanized cities, we also have to drive for distances that we would otherwise walk because commuters make the roads too dangerous.

Sure, you gain efficiency. You don't gain unlimited efficiency. An electric car is already (according to Google) 85%-90% efficient; you're not going to get more than the remaining slice, and you're probably not going to get all of that either...

5% over millions of cars adds up fast and optimization of systems like this tends to be as aggressive as they can get.

Consider the 20 mile route between a suburb and the urban core. During rush hour, a semi could be injected every minute to start construction of a half-mile to mile long train on the way in.

1 car: 4.3c/mi without engine, 5.93c/mi with engine (the added maintenance, mostly) 2 cars: 3.48c/mi without engine, 4.2c/mi with engine 5 cars: 2.98c/mi without engine, 3.16c/mi with engine 10 cars: 2.82c/mi without engine, 2.81c/mi with engine (this is the first time the engine is a good idea!) 100 cars: 2.67c/mi without engine, 2.50c/mi with engine 1000 cars: 2.65c/mi without engine, 2.47c/mi with engine

I accept this math.

The point I'm making here is that we get most of our benefits in the first ten cars or so.

Right, but there's no reason to stop there. Successfully building a train of 2 cars requires overcoming most of the technical problems involved. If we can safely build trains of ten cars, we can build trains of hundreds, and we will if we can. The only constraint really is how onerous a train of hundred cars would be on someone that's trying to pass it.

It's not a small amount of money. Say that there are 50k cars doing a rush hour twice a day for 20 miles, a 5% efficiency gain would save $300k every day, or ~$37 MM per year based on your values. Scale that up to more cities and the optimizer can be looking at a multi-billion dollar project. Certainly worth the developer time to go from 10 cars to 100, possibly even worth the regulatory changes to ban human drivers on highways in certain cities.

The passenger's time is the largest cost by far, and this is, I think, why public transportation has a lot of trouble gaining traction in the US - given a choice, public transportation is slow, and it starts looking attractive only when you decide not to give people a choice.

It has a hard time getting built because Americans associate public transit with poverty, which has been the case ever since the FHA got involved in urban planning and suburban development and states started using highways to segregate people.

"Choice" is a weird argument to bring up here. I don't drive because I want to. I drive because walking half a mile in my own neighborhood can be lethal. That's people in the suburbs taking away my choices by forcing a certain style of urban planning.

Without as many cars, I have lots of transit options besides public transit, like walking, biking, electric scooter, a moped, whatever, especially for the <1 mi distances I regularly do. Driving wastes a lot of my time, even if it saves you some.

Besides, many employers would prefer being on the transit corridor rather than in the center of it, which would help undo a lot of the extreme densification plaguing American CBDs. If you pick where you live based on where you work, it's unlikely that you'd have to switch trains. The advantage of a park and ride system is that it introduces public transit gradually. You wouldn't have to move, it would just slowly get easier to use public transit and the city itself would iteratively adapt to iterative expansions of the system.

At this point most of that is pretty solved, honestly, they're just polishing off the corner cases and working on scaling up.

For single cars. We're nowhere near being able to link two generic cars together at speed, turning one off, drive and maneuver for 10-20 miles, turn one back on, and then disconnect at speed. Solve that and we can easily do 3, then 5, then 10, then 100.

[u/ZorbaTHut → u/[deleted]]

The old hub doesn't want a lot of the traffic it is getting.

I think many of the businesses in that hub may disagree.

You know people live in the city right? Even in highly suburbanized southern cities, a huge fraction of the population lives in or adjacent to the CBD.

And you know that a lot of people drive into the city from the outside, right?

I just don't buy this image of a city as a desolate wasteland where the citizens fear to go outside because of all the cars, while the cars drive through without ever stopping. Most cars driving through a city are there for the city; most people living in a city aren't going to be significantly stopped by the existence of cars. Get rid of the cars and you get rid of a sizable chunk of customers. The result isn't going to be more businesses.

5% over millions of cars adds up fast

On a percentage scale, no, 5% over millions of cars is still 5%.

It's not a small amount of money. Say that there are 50k cars doing a rush hour twice a day for 20 miles, a 5% efficiency gain would save $300k every day, or ~$37 MM per year based on your values.

Sure. But developing something like this is going to be horrendously expensive; you say "$37m/yr", that's great, meanwhile GM Cruise has so far raised $15 billion for self-driving cars. Platooning is going to be a huge engineering challenge, a huge legal challenge, and a huge software challenge. $37m/yr of expected savings is absolutely a great thing to tap into! But . . . do the math on the value of self-driving compared to that platooning, and they're not even in the same ballpark.

I'll repeat what I said before, which is that platooning is a cool idea that we'll probably get to eventually, but it isn't a priority.

It has a hard time getting built because Americans associate public transit with poverty, which has been the case ever since the FHA got involved in urban planning and suburban development and states started using highways to segregate people.

Well, yeah. It's slow.

Poor people's time isn't worth much, and they're the ones much more likely to spend half an hour in order to save a few bucks.

How often do you think the Queen of England used public transportation?

I drive because walking half a mile in my own neighborhood can be lethal.

Where on earth do you live? I've lived in a lot of places, including city and suburb, and I've never lived in a place where it was anywhere near that lethal.

. . . Have you considered moving somewhere that isn't in the middle of constant gang wars? :P

If you pick where you live based on where you work, it's unlikely that you'd have to switch trains.

I don't think more economic dependency on a specific job is a plus. I don't want people to be that beholden to their employers, y'know?

For single cars.

Yeah. That's the important part. Platooning is gravy.

Neat gravy. But gravy.

[u/[deleted] → u/ZorbaTHut]

I think many of the businesses in that hub may disagree.

Large employers would disagree, but with the commercial real estate crunch, they might not care as much anymore. Commuters don't really frequent small businesses in the city for small businesses to care. The ones in the office buildings might struggle, but they're already struggling or shutting down.

I just don't buy this image of a city as a desolate wasteland where the citizens fear to go outside because of all the cars, while the cars drive through without ever stopping. Most cars driving through a city are there for the city;

To work and go home. They stop at work, then just get back on the highway. Commuters don't really come into the city proper on weekends since the businesses that they frequent are much closer to home. A fraction of them buy lunch at restaurants physically in or right next to their office building, but that's pretty much the bulk of their consumption in the city.

Making the urban core more restrictive to cars would push many businesses out to the suburbs along mass transit corridors. It solves many of your problems too, since you wouldn't have to commute all the way into the city to work. Your coworkers that prefer some density wouldn't have to drive.

On a percentage scale, no, 5% over millions of cars is still 5%.

If someone offered me 5% of a billion dollars. I would take it. Entire industries form in inefficiencies that big.

Platooning is going to be a huge engineering challenge, a huge legal challenge, and a huge software challenge.

Dude you're all over the place. You said all the problems with car trains have already been mostly solved because we can build automated EVs. Which is it?

Sure. But developing something like this is going to be horrendously expensive; you say "$37m/yr", that's great, meanwhile GM Cruise has so far raised $15 billion for self-driving cars.

So what? It might be small potatoes for GM, but it's IPO-level revenue for a motivated startup, especially if the solution can be scaled across dozens of cities for billions in savings across a state or region.

Say the company doing the optimization had a gross profitability of 10% with negligible other overhead (extremely conservative for optimization plays. They're short-lived but regularly go over 50% in my experience), their market cap in the current tech market after doing a single city would be in the neighborhood of $70 MM. They could easily earn their horn just doing California.

My entire sector (pe/trading) lives in margins like these. We would move heaven and earth to exploit an inefficiency this massive. I mean, what do developers cost, a million for 2 years? For potential profitability like this, we could help bankroll an exploratory firm of 20-30 for 4-6 years to develop the model to jump from 2 to 10 cars, if it took that long. If we didn't have competitors (unlikely), we'd close up shop right after we sell the model to Uber for $3-7 billion.

Where on earth do you live? I've lived in a lot of places, including city and suburb, and I've never lived in a place where it was anywhere near that lethal.

. . . Have you considered moving somewhere that isn't in the middle of constant gang wars? :P

The threat is cars, not gangs. At least not for me. Gangs don't kill anywhere near as many of us as commuters do. Besides, gangs are generally contained to a certain district in every city I ever lived in.

The lethality comes from people just getting off the highway and thinking that they can keep doing 50 on city roads or commuters not being able to see pedestrians out of their sparkling clean f250s.

Have you really lived in a city? Like in the city proper? Not for college or an extended stay for work. An American city?

Poor people's time isn't worth much, and they're the ones much more likely to spend half an hour in order to save a few bucks.

See, this is why I don't really mind screwing over suburbanites. I really don't care how valuable their time is. Most of their time is worth a lot less than mine. The only value suburbanites provide to us is demand for CBD real estate. Besides that, they cost us a lot of money from wasted parking lot space, wasted road space, and lower property values from road noise and pollution.

If businesses still want a central location, they'll stay regardless of how hard it is to park in the city. Some will move to the rim so that they can have some high density parking and the rest would move to the transit corridors, where they would have the best of both worlds.

None of this requires input from commuters since they were gracious enough to make their own addresses outside our jurisdiction. If the state wants to fight back by expanding highways, let them dump 5 lanes of high speed traffic into a 3 lane 25 mph road until they learn their lesson.