The Los Angeles County Metropolitan Transportation Authority (LA Metro) has goals of an emission free fleet by 2030, making plans to spend $138 million on transitioning from natural gas to electric buses.
LACMTA is now planning how to eliminate emissions from the fleet which means buying 2,300 buses either running on electric batteries or an alternate type of zero-emission source such as hydrogen.
Check out an article from the LA Times: http://www.latimes.com/local/lanow/la-me-ln-metro-electric-buses-20170721-story.html