City planners and citizens alike frequently push for better public transportation¹. They argue that it can lessen² traffic and reduce emissions³ from cars. Now there’s a new reason to be gung-ho about public transit⁴ — it helps make people skinnier. That’s according to a study published in the August issue of the American Journal of Preventive Medicine.

城市规划者和市民都迫切地希望改善城市的公共交通。他们认为这能减轻交通负担，减少汽车尾气排放。如今，《美国预防医学杂志》八月刊上发表的一篇报告，又为改善公共交通增添了一条理由，那就是挤公交能瘦身。

Researchers surveyed communities in Charlotte, North Carolina. One survey was done before the city had finished building a new light rail system, and the second was done from 12 to 18 months after the rail’s completion. They asked about the residents’ level of physical activity, body mass and use of public transportation before and after the light rail.

研究人员在北卡罗来纳州夏洛特的社区内进行了调查。在夏洛特市建成新的轻轨之前做了一份调查，接着在轻轨建成后的12 至18 个月内又进行了一份调查。他们询问了市民在轻轨建成前后的身体状况和体重。

Turns out that people who started using light rail to commute⁵ had a significant average weight loss over that time —equivalent to about six and a half pounds for a five-foot-five person. The users were also 81 percent less likely to become obese⁶ over the time scale surveyed.

结果表明，随着时间推移，使用轻轨通勤的人的平均体重有了明显的下降——一个身高5 英尺5 英寸的人减掉约6.5 磅的体重。使用公共交通工具的人们患上肥胖症的几率降低了81%。

The researchers say that an environment based on mass transit influences health, because rail users are get exercise

研究人员表示使用公共交通能够对人的健康产生影响，因为坐轻轨的乘客在来回步行去车站的时间里就得到了锻炼。由于现在的医疗费用很高，可以说，公共交通系统是在变相地替大家省钱了。