1. There are traffic lights first, then cars. Because before there were cars, there were horse-drawn carriages as the mainstream means of transportation.
2. The world’s first coal-fired traffic light was opened in London on December 9, 1868. However, its original intention of construction and use was to prevent horses from being jammed. This traffic light combined with Three arm signals were installed, and red and green gas lamps were used for night use, while police officers operated levers on the lamp posts.
3. The first signal light powered by electricity was developed by an American police officer in 1912. The signal light also only used red and green lights. As for the world's recognized first car, it is generally defined by the date when Karl Benz, one of the founders of Mercedes-Benz, obtained the world's first automobile engine patent, which was January 29, 1886.
4. So in fact, before there were cars, there were already traffic lights in the earliest sense out of the original intention of keeping traffic orderly and avoiding congestion.