California adopted a plan to convert all city buses in the state to electric power by 2040, and hopes to beat that deadline by five years. 

In terms of cleaning up air quality and improving health, buses can deliver a lot quicker bang for the buck than electric cars. The California Air Resources Board says converting the state's 12,000 buses to electric power will deliver benefits equivalent to converting 4 million cars.

Buses follow prescribed, usually low-speed, urban routes, and the diesels they replace are particularly dirty and inefficient. As an added benefit, buses are used most in disadvantaged communities where pollution is often worse, and cleaning up buses on the streets can make significant improvements.

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They also have dedicated depots where high-powered chargers can be installed, so they can charge overnight and in between schedules throughout the day.

CARB passed the Innovative Clean Transit Regulation  on Dec. 14, that requires the state's 200 public transit agencies to submit proposals to CARB for how they plan to turn over their fleets to electric power by 2040.

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Eight of the state's 10 largest transit agencies already use electric buses. Several companies, including California-based Proterra and China's BYD already build electric city buses.

By 2029, CARB expects all new buses purchased in the state to be electric. By 2020, the effort is expected to increase the number of electric buses on state roads from 153 today to more than 1,000.

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The law is also expected to eliminate more than 7,000 tons of harmful diesel emissions and 19 million tons of carbon-dioxide from the atmosphere by 2050.

"A zero-emission public bus fleet means cleaner air for all of us," said CARB chairwoman Mary Nichols in a statement. "It dramatically reduces tailpipe pollution from buses in low-income communities and provides multiple benefits especially for transit-dependent riders.”

Shuttle buses too

In a separate action, CARB is considering a regulation that will require airport, rental-car, and parking shuttles at the state's 13 largest airports to be electric. That regulation is scheduled for a public hearing Monday, and would require all new airport shuttles by 2026 to be electric or fuel cells.

If the measure is enacted, the state hopes to retire all non-electric airport shuttles by 2035. That measure is expected to reduce toxic emissions by nearly 140 tons and eliminate a half million tons of carbon dioxide from the atmosphere by 2040.