The CTA unveiled new hybrid buses today that plug into an electrical outlet at night and run on battery power for most of the day.
The transit agency is acquiring 150 of the 60-foot-long New Flyer articulated buses by next summer to replace buses dating to 1991 and 1995. So far, 22 of the new buses are in service.
The diesel-electric buses save fuel by running the engine at idle when the bus is operating at up to 25 miles per hour, officials said. Engine power is increased only when the speed exceeds 25 m.p.h., which in city traffic is not often.
Watch a report on the new bus technology: