London's overcrowded bus and subway system might also benefit from the bikes.

VOA: standard.2010.07.30

We have got an extensive subway system and an extensive bus system that we have had for 60, 70 years.

我们有大规模的地铁系统和巴士系统，它们已经有差不多六七十年的历史了。

纽约的公共交通 - SpeakingMax英语口语达人

looked at things like where should they locate waste water treatment facilities because of the impacts of climate change, what risks are likely to occur to their subway system because it's underground and already requires enormous pumping of water during certain large rainfall events."

VOA: standard.2010.06.14

From the tragedy in Moscow's subway, to the 2004 Madrid train bombings and the explosions in London's public transit system the following year, experts say no country is immune to terrorism.

VOA: standard.2010.03.30