Clean Vehicles
CTA hybrid buses significantly reduce emissions compared with conventional diesel buses.

icon Clean Vehicles

The CTA is committed to the goal of cleaner air in the Chicago region. We've achieved significant emissions reductions from our rail, bus and support fleets through advanced vehicle technologies and alternative fuel sources.

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icon Trains

CTA’s fleet of about 1,200 rail cars carries about 40 percent of all CTA rides.

  • Electric rail is a highly efficient motorized transport mode, operating on low-friction steel rails.
  • CTA has begun putting a new family of ‘L’ cars into service, known as the 5000 Series. These railcars are equipped with an innovative braking system that can transfer electricity back to the third rail, supplementing power to nearby CTA trains. 
  • We're studying whether excess energy from braking trains could be captured and stored for later use, further increasing the energy efficiency of the rail system. A study of the Red Line was completed in 2017.

icon Buses

The CTA maintains a fleet of more than 1,800 buses, which carry about 60 percent of all CTA rides. We are continuing to increase the energy efficiency of our bus fleet and reduce emissions.

  • We converted our entire bus fleet to ultra-low sulfur diesel in March 2003, well before the US Environmental Protection Agency mandated its use in October 2006. All buses delivered since 2007 have clean-diesel engines and particulate filters that meet EPA emissions standards.
  • Between 2007 and 2011, emissions of key pollutants from CTA’s bus fleet decreased by the following amounts; emissions are expected to decrease further by 2015 with planned bus fleets retrofits and replacements:
    • Nitrogen oxides: 36 percent reduction
    • Hydrocarbons: 82 percent reduction
    • Carbon monoxide: 55 percent reduction
    • Particulate matter: 53 percent reduction
  • CTA currently operates more than 250 hybrid buses, which make up nearly 15 percent of the total bus fleet.  Hybrid buses achieve at least 20 percent greater fuel efficiency than standard diesel buses.
  • We have completed our first winter season using outdoor power cords to plug in hybrid buses during cold weather. The power cords will allow buses to reduce engine idling, while maintaining customer comfort and operator safety.
  • In 2011, CTA received a $2.2 million federal grant for the purchase of two all-electric buses, which will produce zero tailpipe emissions. The buses are expected to be delivered in late 2013, and CTA will test the buses for approximately one year. 
  • Also in 2011, CTA received federal Congestion Mitigation and Air Quality Improvement Program (CMAQ) grants for installing two bus fuel-efficiency technologies: $900,000 for Topodyne transmission software and $6.2 million for all-electric cooling fans.

icon Support Vehicles

CTA maintains a fleet of support vehicles which are used to monitor bus performance, transport materials, and maintain our vehicles and properties. Our ongoing purchase of low-emissions support vehicles earned an Illinois Green Fleets designation from the Illinois EPA in 2002, and we have increased our fuel efficiency every year between 2008 and 2012.

  • CTA’s support fleet includes the following:
    • Hybrid-electric SUVs, sedans, and pickup trucks
    • Vehicles that can run on E-85 fuel, a blend of 85 percent ethanol and 15 percent gasoline
    • Vehicles that run on clean-burning compressed natural gas (CNG)


icon Video: Hybrid Buses


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