While Natural Gas does not burn as clean as biofuel, it is a viable interim option. It burns significantly cleaner than gasoline and every vehicle we convert to compressed natural gas (CNG) reduces our dependence on foreign oil. There must be jobs for Americans in this equation as well, and I find merits in this potential as long as no damage it done to the environment in the extraction process. When more of our commercial and municipal vehicles run on CNG we will have made a positive step forward. The conversion of combustion engines to burn CNG is a fairly inexpensive and easy transition to make and our air will not be polluted as quickly. As we are evolving to electric vehicles and away from internal combustion engines, CNG provides a good transitional step forward. The following is from Energy.gov.