"At a per-passenger-mile basis, rail is about three times as efficient as travel by car, in terms of fuel efficiency, and six times as efficient as travel by air, so there are pretty substantial pollution reduction benefits both in terms of greenhouse gases and other pollutants."

VOA: standard.2010.02.15

In the meantime, I believe that the U.S. is doing quite a bit of work in terms of raising fuel efficiency standards,

同时，我相信美国在提高燃料效率标准方面做了不少事，

对全球变暖的政策 - SpeakingMax英语口语达人

Liberals say the fuel-efficiency requirements for the replacement vehicles are not strong enough for the environment.

VOA: special.2009.08.07