EDIT: Also, you can't just give it all back. As long as emissions continue at something near current levels, you have to spend it on amelioration. It doesn't just become a slush fund.
I'd say as much of it as we can, equally per-capita.
> Some poor people drive a lot.
And either they will change their behavior, or be hurt less than if we didn't give the money back. As people generally change their behavior they will likely have more options, as demand rises for alternative modes of transportation (and for goods and services that involve burning less gas) leading to greater economies of scale.
> Some poor people don't drive at all.
But they still buy goods that were shipped by burning gas. Even so, they'll benefit more than others, but I don't think that's a problem.
> Also, you can't just give it all back. As long as emissions continue at something near current levels, you have to spend it on amelioration. It doesn't just become a slush fund.
We can certainly talk about taking a piece for amelioration, but I don't think paying that out of the general fund is unrealistic; it's what we'd be doing otherwise, and it'll be way cheaper if people have adjusted their behavior to reflect the true costs of their actions.
The very worst case, of course, is any who find themselves paying higher prices but unable for whatever reason to access the stipend.
Transporting stuff doesn't need to use all that much oil. Neither does growing.
In U.S. budget-ese, you describe costs over a 10 year span, so that's a "$5 trillon tax hike".
The point being that the EV subsidy is small potatoes. I still think it's a bad idea. Tax the gas. Let producers and consumers figure out how to use less, and let governments figure out how to compensate for the regressiveness of the tax.