วันพฤหัสบดีที่ 25 พฤศจิกายน พ.ศ. 2553

First set of traffic lights

First set of traffic lights
First set of traffic lights in Germany on Potsdamer Platz in Berlin

First set of traffic lights in Germany on Potsdamer Platz in Berlin

In 1924, Siemens set up Germany's first automatic traffic signal system in a traffic tower on Potsdamer Platz in Berlin

- the three adjacent signal lamps lit up in red, yellow and green.