Cory DoctorowJun 26, 2024

EVs won't save the planet. Ultimately, the material bill for billions of individual vehicles and the unavoidable geometry of more cars-more traffic-more roads-greater distances-more cars dictate that the future of our cities and planet requires public transit - *lots* of it.

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If you'd like an essay-formatted version of this thread to read or share, here's a link to it on pluralistic.net, my surveillance-free, ad-free, tracker-free blog:

https://pluralistic.net/2024/06/26/unplanned-obsolescence/#better-micetraps

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Pluralistic: Cleantech has an enshittification problem (26 Jun 2024) – Pluralistic: Daily links from Cory Doctorow

Show threadPeter BrownJun 26, 2024

@pluralistic two unintended consequences of the move towards electric vehicles is that they are at their best on short journeys, not travelling transcontinental.
And they are also at their best at speeds under 40 miles an hour, becoming very greedy over 60.

Both of these factors will help modal shift to mass transit across longer distances and should help to reduce average traffic speeds.

Show threadJohn Deters
@peterbrown @pluralistic Almost all passenger vehicles become "very greedy" over 60, regardless of fuel type. EVs just put the power number conveniently on the dashboard so you can see it for yourself.
Jun 27, 2024 at 2:09amWeb
Show threadOggieJun 27, 2024

@targetdrone @peterbrown @pluralistic
You know what the single biggest trend that lowered fuel usage and also lowered average car speed across the board, when they finally did a huge study over it? (I wish I could find the in depth thing, but my google-fu is weak)

It was the move to show active efficency on the dashboard. It turns out, if you see that your fuel MPG (this was pre electric) drops when you do something, the average driver...doesn't do it as much.

Always stuck in my brain.

Show threadDominicJun 27, 2024
@targetdrone @peterbrown @pluralistic ... because air resistance becomes very significant. It would be much better if cars could drive very close behind each other, so the first car pushes the air out of the way, and the rest ride along in the slipstream. This would require very advanced self driving or perhaps even better just mechanically coupling the cars together so they all move as one long unit...
Show threadahoyboyhoyJun 27, 2024
@dominic @targetdrone @peterbrown @pluralistic huh, never considered coupling cars together... into a... train. Damn, we already had the answer all along, again!
Show threadDominicJun 27, 2024
@ahoyboyhoy @targetdrone @peterbrown @pluralistic you could make it even more efficient by replacing the relative rough road, and soft tires... with something really smooth and hard. You could eliminate most of the rolling resistance that way. Perhaps you could even have the road configured with grooves the wheels fit into so you don't even need to steer, like mechanical "self driving". It would also be much cheaper than making a whole 2d surface the car can move around on when it only actually wants to move _along_ it. So, long skinny hard smooth roads.... could call it a "rail road" or something!?
Show threadJohn DetersJun 30, 2024
@ahoyboyhoy @dominic @peterbrown @pluralistic The concept has been bandied about for decades. One car acts as a pilot, and as cars enter the road traveling in the same direction, they would auto-navigate to follow the previous car just inches apart. The problems are in the safety: what happens when a system fails, or a pilot makes a bad decision, etc. Plus nobody would want to be the pilot, because they still have the expense of breaking wind.
Show threadahoyboyhoyJun 30, 2024
@targetdrone @dominic @peterbrown @pluralistic not to mention that we could just build more rail and then focus additional efforts on last mile optimizations.
Show threadDominicJun 30, 2024
@targetdrone @ahoyboyhoy @peterbrown @pluralistic take turns bring in front of course
Show threadListerine Lavender MintJun 27, 2024

@targetdrone @peterbrown @pluralistic

I was told once this is because at lower speeds, the dominant component of drag is linear since the air is only compressed around the car. At higher speeds, the drag is proportional to the velocity squared since the air is actually accelerated.

Whether that’s specifically the case or not, there’s a velocity-squared component that’s negligible at low speeds and dominant at higher speeds.

Show threadPeter BrownJun 27, 2024
@thedansimonson @targetdrone @pluralistic I understand that after 30 mph the car will spend more energy pushing air than it will pushing the car.
Show threadListerine Lavender MintJun 27, 2024
@peterbrown @targetdrone @pluralistic as someone who bikes regularly, this doesn’t surprise me in the slightest. You can feel that difference as you get up towards 30 mph
Show threadPeter BrownJun 27, 2024
@thedansimonson @targetdrone @pluralistic yes, pedalling downhill into a headwind is extremely frustrating!!
Show threadToken Sane PersonJun 27, 2024

@thedansimonson @targetdrone @peterbrown @pluralistic

Its worse. The *drag* (force required to keep the speed constant) is proportional to the square of the speed, as you say. But *work* (the energy required) is the force times the distance, and the distance per unit time also increases with the speed. So the *power* (energy per unit time) increases with the *cube* of the speed.

So 2x speed means 8x power. But you get there in half the time. So only 4x the energy.