The paper gives results of a preliminary assessment of the Hydrocarb Process which indicates that substantially more fuel energy can be produced--and at lower cost--than other current options for mitigating carbon dioxide (CO2) from mobile sources. The incremental cost of eliminating net CO2 emissions is estimated at $0.05 per gallon (3.78 liters) of gasoline displaced by methanol. About 80% reduction should be achievable at no incremental cost. It is concluded that, by sequestering byproduct carbon and replacing petroleum fuels with biomass-derived methanol, the Hydrocarb process can nullify the net effect of CO2 emissions from motor vehicles.