If the article posted last week is to be believed [1], which I do, then transportation makes up a relatively small portion of emissions (14%).

Also, the demand for gasoline is very inelastic. Very little driving done today is for pleasure, so the cost would have to be raised so much that people are reducing driving out of necessity/looking for alternatives.

Finally, consumption taxes on necessities act regressively (ie the poor are taxed proportionally more than the rich).

[1] https://www.gatesnotes.com/Energy/My-plan-for-fighting-clima...