3 ms·
What do you mean by constant multiplicative factor’. Are you saying that cars are perfectly balanced between front and back axels (surely a reasonable thing to
by dan-robertson 3y ago
What do you mean by constant multiplicative factor’. Are you saying that cars are perfectly balanced between front and back axels (surely a reasonable thing to want for tyre wearing if nothing else). The point about the scaling is that it is not linear: if you double the weight over an axle, you get 16 times the wear but perhaps 1.5-2x the fuel consumption. For this reason I dispute that fuel duty effectively taxes the (externalities due to the) weight of cars. Though I concede that wasn’t really the point you were making.
- kergonath 3y ago> What do you mean by constant multiplicative factor’. Are you saying that cars are perfectly balanced between front and back axels (surely a reasonable thing to want for tyre wearing if nothing else). Right. An implicit assumption was that the weight repartition does not change much, i.e. that if 2/3 of the weight is supported by the front axle, that ratio would be similar for a hatchback and a SUV. This does not seem completely unrealistic when comparing ICEs with other ICEs or EVs with other EVs (though EVs will have a very different weight repartition compared to ICEs due to the way batteries and motors are integrated). With this in mind, the front axle bears 2/3 * m_1 for a sedan of mass m_1 and 2/3 * m_2 for a SUV of mass m_2. So the effective weight (as seen considering only one axle) is just a linear function of the actual weight. It changes the magnitude, but it does not change the scaling.