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A History of Clean, Green Bus Fuel

When it comes to reducing harmful bus emissions, OCTA leads the pack. In 2000, California established emission requirements for diesel particulate matter (PM) and oxides of nitrogen emissions (NOx) from urban buses and transit fleet vehicles. Transit agencies were required to select either the diesel path or the alternative-fuel path. OCTA selected the cleaner alternative fuel path and has exceeded all state emission requirements for an urban bus fleet as well as for transit fleet vehicles.

OCTA operates more than 500 fixed-route buses in Orange County. The majority of the fleet features near zero-emission engines that run on clean-burning renewable compressed natural gas (CNG). This environmentally conscious fuel is produced by the decomposition of organic matter from landfills and other sources and then processed to purity standards.

As part of its plan to convert the OC Bus fleet to 100 percent zero-emission technology by 2040, OCTA is conducting a pilot program using plug-in battery-electric buses and hydrogen fuel-cell electric buses. This pilot will help determine which technology - or mix of technologies - will help bring even cleaner air quality to Orange County.

Environmental Benefits

OCTA's commitment has resulted in:

  • Compared to 2002 baseline emissions, OCTA reduced its PM emissions by 97 percent and NOX emissions by 99 percent after choosing to use alternative fuel.
  • CNG fuel is safer than gasoline and diesel because it is non-toxic and does not contaminate ground water.
  • When OCTA switched to CNG engines and cooling systems in 2016, it destroyed the old engines and provided documentation of that work to the South Coast Air Quality Management District, which in return provides funding to help pay for the project.

Additional Resources

On April 22, people around the world will join together to raise environmental awareness as part of Earth Day, an annual time of recognition that began in 1970 to protest smog, pesticides, and other pollutants.
Late last month, OCTA CEO Darrell Johnson and OCTA staff gave Federal Transit Administration (FTA) Acting Administrator Carolyn Flowers and Vincent Valdes, FTA’s Associate Administrator for Research, Demonstration and Innovation, an overview of OCTA’s latest transportation services and projects.