Carbon taxes may generate a lot of revenue but at the current gasoline prices I'm not sure they'd affect consumer behavior much. Correct me if I'm wrong but $50 per tonne would increase the price of gasoline by 50 cents a gallon which would still be much less than the prices of 2014 which appeared tolerable to most North American consumers. Even when the economics work for hybrids as they did in 2014 they are still a hard sell. Stopping consumers from buying gasoline is going to take aggressive and unpopular policies. Much easier for a Chinese dictator to implement than a leader of a democratic country although somehow northern European leaders are able to have some success.

Economist like the sales tax and think the CAFE standards are a waste.

http://www.economist.com/blogs/freeexchange/2015/07/reducing-carbon-emissions

They make a good case that the public needs some education on the subject and politicians need to move the public opinion, as well. I do think a carbon based tax would be the only fair way to go about it. Otherwise everyone would be move to highest carbon fuel for max MPG. That being said, it is interesting that the Cummins E85 engine surpassed gasoline on MPG. So, gas has 19.6 pounds of carbon per gallon as opposed to ethanol's 12.73.

It is my opinion that we should progressively phase in a carbon tax. However, I am not holding my breath on this. Just because it would be a smart policy will not make it happen. I do understand why the major vendors want some certainty about future regulations as it allows for rational future planning.

CAFE standards don't affect consumer behavior post-sale (proven by the massive gap between EPA mileage and actual fuel consumption), carbon taxes will.  Arguably an adequate carbon tax will make CAFE standards irrelevant.

Carbon taxes applied across the board will affect the electric market before the vehicle market.  $100/tCO2 adds about 3.3¢/kWh to the cost of power from NGCC plants, over 5¢/kWh to open-cycle plants.  This is roughly double the current price disadvantage of nuclear power in "deregulated" markets.  If the unreliables have their absolute grid priority taken away so that grid operators can curtail them to allow clean base-load to operate, we'll see a lot of interest in new clean base-load with cheap charging for PEVs overnight.  This gets straight to the root of fuel consumption and direct displacement of carbon-emitting fuels.

$100/ton pricing would fly and be embraced by Trump supporters if the Left would compromise. Meaning to give up something of government control and current tax load in return. It would have to be a big bone, but that's the way.

A nuclear base load with smart grid interplay to maximize the utilization. Makes a lot of sense as compared to attempting the same with unreliable's. The cost of the project would be less as well as magnifying the benefit. Funny, everyone trying to make unreliable power replace conventional grid and forgot that just improving utilization of base load can do more and do it cheaper. Currently, we may have the strategy backwards.

A good analogy of unreliable power is the wind turbine water pump for live stock. Wind power utilized in remote non grid rural area. The need had maximum flexibility, as the cattle could go thirsty for a while and the stock tank did have cheap storage. So, we need some inventiveness to utilize more wind power at remote location that have large energy needs, but can operate with non dispatchable electricity production. There should be applications for this if we can invent flexible usage or where most of the product cost is power. Hydrogen gas, aluminum production, kilns, fertilizer production, chemical production, cement production, processing, etc. If would be a new class of manufacturing. A lights out unattended operation that can switch on and off upon power availability. It would need low cost hardware and the transportation cost not a primary limitation.

"CAFE standards don't affect consumer behavior post-sale"

because gas is under $2 where I live.