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Collectively it's not totally unreasonable to limit things for environmental reasons (afaik the reduced fuel consumption in light of the Ukraine invasion might
by hansvm 5y ago
Collectively it's not totally unreasonable to limit things for environmental reasons (afaik the reduced fuel consumption in light of the Ukraine invasion might finally provide the impetus for limiting the Autobahn a little) -- laws exist to balance the desires of people, and the desire to drive faster might be found legally to be less important in its totality than whatever miniscule impact a 20% reduction in CO2 might have.
The stats seem off though, almost exactly as if they normalized by time rather than distance. Most cars increase their fuel economy till 40-50, and the only way you'd see that significant of a jump in CO2 emissions per mile from 30 -> 36 is if it were coupled with an insane amount of stopping and also waiting to stop as long as possible so that the excess energy would have to be consumed by your brakes rather than air resistance (if you have regenerative braking obviously that point is a bit moot).
- sbradford26 5y agoMost likely it is theoretical fuel efficiency and not real world. A car will get it best fuel economy when traveling at the lowest speed where the engine can reach its peak efficiency band. You are fighting the least amount of air resistance and consuming the least amount of energy. Now in the real world this doesn't work out as well since where you drive at lows speeds tend to have a lot of stops. Where usually as once you hit 45-50 mph the roads will most likely have fewer stops.
- hansvm 5y agoAh, so maybe their models are just too simple? The 40-50 band being more efficient isn't just a function of stopping frequency -- you can directly measure it on your favorite long, stop-free stretch of road. Your engine has a nonlinear efficiency with respect to throttle position and load, and at low speeds those dominate fuel economy rather than increased air resistance. An engine optimized for efficiency would of course drive as slowly as possible, but other factors also contribute to the design of modern car engines.