A mainstay of cargo transport will be phased out at ports as California bans new registrations of carbon-fuel trucks in favor of nonpolluting ones.
When not driving around, electric buses and other vehicles could help utilities by storing their solar and wind energy and releasing it to meet surges in demand.
The new low-emission zone appears to be the most ambitious in Western Europe, and it is set to become law in little more than a year.
At the Glasgow climate summit, the transportation secretary said the U.S. would not join a global pledge to phase out gas- and diesel-powered cars.
A scandal led to a $2.9 billion trust fund for states to put cleaner vehicles on their roads. A lot of the money has gone to more diesel vehicles.