Ban carbon dioxide emissions and you ban the internal combustion engine. Ban the internal combustion and you ban driving for everyone who can’t shell out the money for an electric car. That may have been the plan all along. From Eric Peters at ericpetersautos.com:
It didn’t work last time – but this time is different.
Last time, the method deployed to get rid of cars – or at least, cars for us – was emissions standards. The plan was to lay down requirements so severe that cars couldn’t be made to comply with them.
It was a brilliant idea. Don’t tell them you’re anti-car, just anti-pollution. Don’t ban cars, just require them to be ever “cleaner.” Until you can’t build cars that are “clean” enough. 
At first, the plan appeared to be working.
Muscle cars were the first to be gotten rid of. By 1975 – the first year for catalytic converters – there were no more muscle cars. Just a few cars that looked like muscle cars such as the gimping-along Pontiac Trans-Am, Chevy Camaro (no more Z28) and of course, the Corvette – which didn’t come with anything stronger than a 205 hp 5.7 liter V8.
Engines were strangled into compliance. Literally. Dual exhaust disappeared. Exhaust piping got smaller. Airflow to carburetors was restricted in the manner of putting a pillow over the face of a sleeping victim and holding him down with it until his sleep became permanent. Carburetors went from four to two barrels and were adjusted to suck as little fuel as possible.
And the cars began to suck.
Once the gas tax revenue starts going down, a tax on number of miles driven(of course, increasing rates of taxation will be wedded to increased miles meandered) seems to be a distinct possibility.