1 janv. 1920 - Automatic Traffic Light
Description:
In 1920, William Potts developed several automatic traffic light systems, including the first three-color signal, which added a yellow "caution" light. Traffic lights (red, green and yellow) help people drive through intersections safely. They also help people walk across the streets safely. The lights allow people to take turns on the roads.https://www.livescience.com/57231-who-invented-the-traffic-light.html
Ajouté au bande de temps:
Date:
1 janv. 1920
Maintenaint
~ Il y a 105 ans