That's hard to do in practice, I think. To take the inverse example: in NYC tolls on cars are used to pay for capital projects for the public transportation system. If these "independent" components were truly as independent as you imply income taxes + fares would cover the MTA, but they don't.

Each style of transportation is going to have different levels of cost associated with it, likely changing as one or the other has seemingly stable infrastructure for its needs at the time. It really seems like a more useful perspective is to look at the transportation system as a whole and consider any contribution to car infrastructure, public transport, etc as a contribution which makes the whole system better as a whole.

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nehal3m 6 days ago | parent [-]

That's not an unreasonable take in my opinion, but then the point of the person I'm responding to is 'let's silo costs and let the market decide' and if we're going to do that, however unpractical, I'd bet a lot of money that driving a car would become unaffordable.

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Ajedi32 5 days ago | parent [-]

I'd take that bet, were I a betting man. There are 0.85 vehicles per capita in the US. Making roads an average of 1/0.85 = 17.6% more expensive for car owners is very unlikely to break the bank for any significant number of people.

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nehal3m 5 days ago | parent [-]

The current cost of owning and operating an automobile is around 12K USD assuming 15K miles driven yearly according to BTS [0]. This would push it up to a little over 14K USD.

Then there's oil and gas subsidies that should be taken into account, since around 24% of oil consumption is from cars and light trucks. [1]

Then there's some other factors that are hard to quantify but have a huge impact on taxes, like how low density suburbs are subsidised by high density cities [2] as an effect of car-first infrastructure. It's not as simple as just the cost of roads.

[0] https://www.bts.gov/content/average-cost-owning-and-operatin...

[1] https://carsbibles.com/what-percentage-of-oil-is-used-for-ca...

[2] https://www.youtube.com/watch?v=7Nw6qyyrTeI

	▲	Ajedi32 5 days ago \| parent [-]
		This wouldn't increase the total cost of "owning and operating an automobile" by 17.6%, just the portion of that which funds road construction. Hard to quantify exactly how much that is since it's currently just part of your taxes. I don't think it's included in the BTS numbers. At the federal level at least it's pretty insignificant, only 2% of the Federal budget at most (I doubt most would even notice a 17.6% * 2% = 0.35% increase in their federal taxes). If I'm reading things right, the DOT budget is an even lower percentage of my state taxes. I think most road construction is funded at a more local level than that though so it's hard to say the exact impact without looking at individual villages/towns/cities. Oil and gas subsidies are an entirely separate debate which would have almost no effect on the costs of some types of cars (electric) anyway, so it's rather pointless to bring up in this context. That Not Just Bikes video isn't showing "low density suburbs" being "subsidised by high density cities", it's showing low density parts of a city are subsided by high-density parts of that same city. That's still a fair point, but when I think of the suburbs I think of areas outside city limits, usually with their own separate governments and separate tax system. Those survive just fine without any such subsidies; low density parts of a city would be fine without them too.