Until I came across this photo, I’d only ever seen two types of traffic signals: the three lights in a vertical row that we’re all used to, and the semaphore type with the two lights and the alternating “STOP” and “GO” flags that popped up. But in this photo from circa 1924, we can see an experiment type with three bands of horizontal lights, which I can only assume were the traditional green, amber, and red. These men were on the busy intersection of W. Adams Blvd and S. Figueroa St, not far south of downtown Los Angeles and, quite fittingly and not coincidentally, near the headquarters of the Automobile Club of Southern California.
Here is the story of that traffic light, the “American Bobby”:
https://metrosetter.wordpress.com/2013/01/10/a-peep-into-los-angeles-history-traffic-signals/
Thanks for the link, David. It’s interesting reading. I would also have thought that the semaphores went in earlier than 1920.
When I worked for the City of Los Angeles Department of Transportation I researched the history of traffic control devices. Below is what I discovered.
Although the first experimental Acme traffic signal was activated in October 1920, Los Angeles experimented with other types into 1924. (Try to find a photo of the intersection of Wilshire Boulevard and Western Avenue circa 1923 which shows the “American Bobby” experimental signal). During the experimental period the Automobile Club of Southern California continued to play an active role in new traffic control, as they had done with guide signs, by installing their own version of a traffic signal in 1924 in front of their headquarters.
The top section read “GO”, the middle section “CAUTION” and the bottom section “STOP”, presumably with green yellow and red colors, respectively. It was placed in the middle of the intersection to maximize visibility. Although the Acme became the standard for the City by the end of 1924, the Auto Club signal was allowed to remain. However, it was inevitable that the signal in the middle of the intersection would be hit and damaged. When this occurred in 1930, the City’s first traffic engineer, Ralph Dorsey, replaced it with an Acme.
Hey John, thanks for all that background info. Fascinating!