The use of alternative fuels holds the promise of promoting energy diversity and reducing motor vehicle emissions. With the passage of the federal Clean Air Act Amendments of 1990, the National Energy Policy Act of 1992, and state initiatives, these fuels will have a far reaching influence on the fuels motor vehicle fleets operate on during the next century. To ensure good emissions performance from vehicles converted to alternative fuel, the Colorado Department of Health has implemented an alternative fuel retrofit system certification program, and an in-use emissions test program for alternative fuel vehicles. Results from the in-use test program indicate that further work is needed to maintain current emission standards from converted vehicles. In the future, it is expected that EPA and California certification standards for both new and converted alternative fuel vehicles will ensure that alternative fuel vehicles will meet required low emissions standards. (A)
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