翻译

　　It took many years to develop the traffic lights we know today. In fact, the first-ever traffic light is actually older than cars. It was installed outside the British Houses of Parliament in 1868. It consisted of the revolving gas lamp, which police officers used to control the heavy horse-and-carriage and pedestrian traffic that was common at the time.

　　The advent of the automobile made directing traffic by hand less and less practical. 1. 因此，感到挫折的美国消防员和警员不停寻找能够改善城市车流量的方法。 The first electric design for a traffic light came from Salt Lake City, Utah, in 1912. Like London's original light, it was controlled by hand. Between 1918 and 1923, several designs for traffic lights using different colors and buzzers were successively trialed.

　　In 1920, police officer William Potts decided to apply railroad technology to the road. These signals were already automated and therefore needed no hand operation. 2. Potts 将黄色的警告灯加入到传统的红灯和绿灯中，于是现代的红绿灯就此诞生。

1. 第一句可译为：

Therefore, frustrated American fire fighters and police officers kept searching for a way to improve their city's traffic flow.

2. 第二句可译为：

Potts added the yellow warning light to the traditional red and green, and the modern traffic light was born.

 

　　历经多年，红绿灯才演变成现今我们所知的样貌。事实上，史上第一座红绿灯实际上比汽车还要来得古老。它是在 1868 年装设在伦敦议会外。它包含了旋转的气灯，警察用它来指挥繁忙的马车及行人，这在当时很普遍。

　　汽车的出现使得用手来指挥交通越来越不实际。因此，感到挫折的美国消防员和警员不停寻找能够改善城市车流量的方法。第一座红绿灯电动装置的设计于 1912 年出现在犹他州的盐湖城。如同伦敦最初期的红绿灯，这项装置也是由人工操作。1918 年到 1923 年间，好几项红绿灯的设计相继出现，他们使用不同的颜色及蜂鸣器作试验。

　　1920 年，William Potts 警官决定把铁路的技术应用到马路上。这些号志灯已经自动化，因此不需用手来操作。Potts 将黄色的警告灯加入到传统的红灯和绿灯中，于是现代的红绿灯就此诞生。