In June 2010 COTA introduced six hybrid buses, which offered a 48 percent increase in fuel efficiency over its diesel buses, a battery-powered electric motor and regenerative brakes that power the battery when pressed, an LED lighting system used inside and outside of the vehicle, and a smoother ride for passengers since the electric motors do not require shifting. Due to rising gas prices at the time, COTA was concerned with reducing fuel emissions, which sparked the addition of the hybrid-electric buses. In 2011, COTA conducted a study to consider potential benefits of switching to compressed natural gas (CNG) to power its fixed-route bus fleet. The study compared costs of CNG versus diesel fuel, operational and maintenance expenses, market forces and infrastructure costs. In keeping with COTA's "Going Green" program, environmental impacts, particularly emissions, were also evaluated. COTA officials also visited and studied other public transit systems operating CNG fleets. In late 2011, COTA made the decision to move forward with the transition to CNG and updated existing plans for the renovation of the McKinley Operations facility to include CNG compatible modifications. COTA completed a $76 million renovation of its McKinley Avenue Fixed-Route Bus Operations and Maintenance Facility. The facility is the larger and older (completed in 1974) of its two fixed-route operations facilities.