1920s Traffic Laws and Technologies

The 1920s are well known as a decade when automobile ownership in the U.S. skyrocketed, especially with the production of Henry Ford’s Model T. But an equally fascinating aspect of the story is how municipalities tried to cope with the sudden explosion of automobile traffic on the streets. All of the road signs and signals that we are so used to seeing today–a double yellow line down the center of the road, a white pedestrian crosswalk, the traffic light in the intersection–did not simply spring into being when the first cars drove down the road. They had to be invented, and there were lots of false starts along the way. One of my favorite examples of a traffic technology that faded into obscurity is the mushroom traffic light.


(Source: The American City [May 1921])

Cities experimented with painting various signals on the road too. In the mid-1920s, some began painting a white line down the middle of the road to separate traffic. Before that, there were no lane markings. As my next novel is set in Los Angeles in 1925, I’ve been researching traffic laws there in particular. In January of that year, LA passed a new traffic ordinance. This required the police to paint white crosswalks for pedestrians and also established the first loading zones on curbs. Speed limits included 20 mph in residential areas, demarcated by a sign shaped like a triangle and painted red.

To make things really confusing, every state and every city was experimenting with their own system. So in one city you might find mushroom traffic lights, in another lights hanging above the road. One city might paint signals on the road, while another relied on signs.

At this time, if police stopped you for violating a traffic law, they didn’t write a “ticket.” Instead, it was called a “tag.” So policemen “tagged” offending motorists.

My main character is a motorcycle patrol officer with the LAPD. Enforcing traffic laws might sound dull, but in fact, this was a remarkable period in which cities adapted to automobiles and created the landscape of traffic signals and signs so familiar to us today.


Sources: California Motor Vehicle Act of 1925; “Heath Reports Need of Police,” Los Angeles Times, July 15, 1925; “New Los Angeles Traffic Code Goes Into Effect Next Saturday,” Los Angeles Times, January 18, 1925