Atlanta wants to shuttle Olympic athletes on natural gas buses next year.
This would have overwhelmed any cost advantages for the compressed natural gas buses.
The city has ordered 125 more, expected to be in service by late 2001, along with 135 natural gas buses.
A hybrid bus costs about $385,000 and a natural gas bus is about $325,000.
Beijing has added 3,800 natural gas buses, one of the largest fleets in the world.
The authority hopes to have the gas buses on the road by the middle of next year.
The bureau also employs relatively many low pollution vehicles as Japanese bus operator, including 157 natural gas buses.
So far, the authority is operating 221 natural gas buses, and plans to increase its fleet to 650.
In 1999, the first liquified natural gas buses were introduced to the bus fleet.
But advocates of natural gas buses have questioned the conclusions drawn by both of those studies.