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 DetersJun 27, 2024
@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.
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 threadToken Sane Person

@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.

Jun 27, 2024 at 7:13amWeb