If this refers to the unpaid-externalities, I don't think that argument works on most people because they figure that if they're getting away without paying for something currently, then it must not need to be paid for.

As for paying tax for cars, I wonder what the percentage of various costs, prices, fees, etc. would be if you calculated how much of what you pay goes toward paying automotive expenses. Considering that even the lowest-wage employees drive cars, it would be significant for every business or organization. Then consider how much higher everyone's rent is because rent has to cover automotive expenses of landlords.

That means you're paying automotive expenses twice; once for people as part of their wages, a second time for their landlords as part of their rent-allowance. Then consider that all their other costs are also paying for other people's driving. Now you start wondering how much the cost of everything would go down if everyone wasn't paying everyone else's driving expenses.

If you just count it as a percentage of GDP, everything else seems to overshadow it because those costs factor in the driving costs as well. But when you consider that all the other costs you're paying, from insurance, to rent, to groceries, to clothes, all have driving expenses factored into them, the percentage would be much higher.