According to the fifth annual Traffic Index report released in March by GPS manufacturer TomTom, traffic in Los Angeles is literally the worst. But the county’s traffic woes were set in motion, so to speak, long before it would see the population boom of the 20th and 21st centuries. From 1895 to 1945, the Los Angeles Railway, or “Yellow Cars” as they were known, replaced cable cars as the city’s main mode of transport. For a time, it was part of the largest urban rail network in the world, and the Yellow Cars were known for years as “the vital cog in the city’s transportation system.”

As time marched on, yellow cars would go the way of cable cars before them. Automobiles became the favored mode of transportation in the 1950s, and they might have had some help, too. According to a popular theory, automotive interests, led by General Motors, bought up a number of streetcar lines and converted them to bus routes. If this sounds familiar, it might be because this story also found its way into the plot of 1988’s Who Framed Roger Rabbit? The automotive interests acted in the name of increasing sales, but today’s studies suggest that a number of post-WWI economic factors would have caused street cars to become obsolete in any event.

L.A.’s first freeway, the 8.9 mile, six-lane Arroyo Seco Parkway—later known as the Pasadena Freeway—opened in 1940. Many would follow, but not nearly as many as the city planners originally intended. Throughout the ‘40s, ‘50s, and ‘60s, construction tore through L.A.’s mountains and communities in the name of a 527-mile freeway system. Businesses and homeowners were evicted and displaced, and these freeways created a divide between homes that once belonged to the same neighborhood. Many more roads were supposed to be built, but these never came to fruition, and their absence can be seen in some of L.A.’s most congested areas.

By the late 1960s and early 1970s, construction halted. Some blame then (and current) Governor Jerry Brown, while others blame the rising costs of building modern freeways. In certain cases, it was the successful protests of affluent communities that stopped development. L.A.’s Eastside faced the worst of the construction, as its residents lacked the resources to fight back against those in power. (The east vs. west L.A. split is one that existed before freeways, and it still remains today.)

There’s now no more room in L.A. to build additional freeways, and even if there were, studies show that expanding roads would actually create even more traffic. On top of that, updating current freeways is expensive enough and takes years of construction. Of course, it also doesn’t help that L.A. is the most populous county in the United States.

In recent years, the county has made concerted efforts to encourage “choice” riders—those with options beyond buses—to take mass transit. You might be surprised to learn that, according to a 2011 report from the Brookings Institution, L.A. actually gives the carless more access to public transportation than any other major metropolitan area in the country. Yes, even New York City. Yet only 25% of choice riders take the bus. This lack of enthusiasm for the bus by those who can afford not to take it is just one more cause of the traffic jams you’ve heard so much about.

Los Angeles has its work cut out for it when it comes to reforming their roads and transit system, but they're trying to come up with new ideas. A few years ago, L.A. brought back the 19th and 20th century streetcars—the same ones originally put to bed by automobiles. One person who would probably be a fan of this renaissance is Eddie Valiant, Bob Hoskins’s character from Who Framed Roger Rabbit? He tells a kid, “Who needs a car in L.A.? We have the best public transportation system in the world.”