The problem I have with rationing is it’s a heavy handed solution that will be nearly impossible to win public support for. It will require a huge bureaucracy to administer and enforce and will necessarily involve harsh fines, or even jail time, for those who find a way around the austerity measures being imposed. Naturally, as is always the case with rationing/prohibition, it will also inevitably give rise to a black market for the more popular services or products being rationed.
Most of these problems can be avoided by simply making the fuels we want to eliminate more expensive over time. In addition, this will spur far more innovation than rationing in the long run. If the additional revenue generated through carbon taxing or other carbon pricing mechanisms is simultaneously used to improve certain services and raise the standard of living for the least fortunate, this solution will also be considerably more politically viable than limiting the number of gallons of gasoline people can buy in any given month. Besides, if the price of gasoline and other fossil fuels is going steadily up, people will have every reason to switch to more efficient vehicles and make other more sustainable choices on their own without needing the government to order them to do so. If they choose to continue wasting resources the penalty for doing so is built into the choice.