Obviously the solution to reducing U.S. on-road carbon emissions is consuming less petroleum motor fuels. What this article and referenced study over look is the fact that cellulosic biofuels have negative NEV’s or consume more fossil fuels energy than is produced in the biofuel finished product, EV’s are hardly carbon free including the full lifecycle emissions and power generation sources, and the fact that the behavioral change begins with substantially reduced vehicle usage, or VMT’s. What’s the odds of U.S. residents largely getting out of the vehicles and staying at home most the year in the future? If social media is the center to your life, maybe not a big change. If you must commute to your job, like to take vacations to see the country/world, or need to access most goods and services (food, medical care, clothing…) more than a few blocks from where you live, the assumptions used in this reduced highway carbon study may not be very feasible.