Like most Angelenos, I have spent way too much of my life driving through the area’s freeway system. It is a system that is alternately beloved and reviled. The freeways helped to propel the area’s growth, but at a cost to the environment and to the surrounding neighborhoods that is incalculable.1
But I am using this space to write about just one aspect of the Los Angeles Freeway System: the interchange. For the most part, people just don’t take one freeway for a trip. We rarely seem to go straight north-south or east-west. We need to go from Granada Hills to Palms. We have to go from West Covina to Downtown. We drive from Santa Clarita to Long Beach. We are people who go from the 605 to the 105 to the 710 freeways just because the first two freeways numbers add up to the third one.2
When the freeway system was being constructed, with the small Arroyo Seco Parkway before World War II, then, in the late 1940s and throughout out the 1950s LOTS of other parts, but the freeways were first built as discrete parts and if you wanted to go from one to the other, you had to get off the freeway, drive on a surface street, and get back on. 3
But the California Department of Highways (not yet Caltrans, which started in 1972) started building interchanges. Some of the interchanges were small, mostly from the Arroyo Seco Parkway (which was soon to become the Pasadena Freeway and then later changed back about 15 years ago after people argued that there is no part of the freeway in Pasadena.)
But in 1953, the Highway Department, after two years of monitoring the area and construction, was ready to unleash its beast. It would be the interchange that would supposedly revolutionize how highways intersected. It would become known as the Four-Level Interchange, aka The Stack, aka The Mixmaster, aka The Bill Keane Memorial Interchange.
This interchange brought together the Arroyo Seco Parkway, which became the Harbor Freeway as it passed through Downtown and the Hollywood Freeway, which changed its name to the Santa Ana Freeway. If you’re looking on a map now, it’s SR 110, I-110, and US 101. 4
All of the possible permutations of freeway connections were possible. You want to go from the 101 North to the 110 South? No problem. 110 South to the 101 South? We can do that too.
What made the Four-Level Interchange so revolutionary (it would remain revolutionary for about 1-2 years) was that vehicles could supposedly switch to a different freeway fairly easily because all the traffic would be going about the same speed. It also took up far less area than the cloverleaf interchanges that were being built in other parts of the world. But it never really quite worked out as smoothly as planners thought it would and it is a good place to spend 20-30 minutes of your life at times.
One of the busiest connecting parts of the Four-Level in the morning commute is where the 101 South (Hollywood) connects to the 110 South (Harbor) on the north edge of Downtown L.A., just south of Sunset.
The cars leaving the 101 have two options. They could be getting on to the 110 South and going to locations further south, such as USC, LAX, or San Pedro. Or the people could just be wanting to exit the freeway at one of the Downtown exits. The 110 South people can continue travelling south if they want, but if they want to get off at a Downtown exit, they now face a problem. And it’s a problem I face most days of my life.
The traffic on the 110 South has generally slowed down to around 15-20 mph by the time it hits the 101 interchange. The cars on the 101 going on to the 110 usually are going 20-30 mph faster.
The 110 South drivers who want to get off the freeway have to start changing lanes to the right and have to slow down further. The 101 drivers however need to change lanes to the left and need to speed up. The interchange has connected two sets of traffic with different goals, directions, and speeds.
Nearly every morning, I somehow successfully traverse this part of the freeway and get to my desired off ramp (4th Street) and live to tell the tale. In nearly 30 years of driving this, I have only seen two cars run into each other once and they were glancing blows.
Somehow, I have never been able to get over the anxiety of this 2-3 minute traffic situation. I try to avoid it when I can. It’s much harder to change lanes to your right than your left because you have much better visibility on the left side. This could explain why I never am bothered by the short onramps that the 110 Freeway in places like Avenue 43.
By 1959, the State Highway Department hatched a new scheme for an even bigger interchange that would follow a “spaghetti bowl model.” This is what we call today the East Los Angeles interchange. The engineers built the interchanges at the same time as the freeways to save time.
You can compare the 1959 plan to a current map.
Caltrans has tried all sorts of types of interchanges in the intervening years. All of them are places where traffic gets gummed up. Because the Los Angeles area has millions of people with cars and there is only so much roadway that can be built.
In researching this, I know that this September 22 will be the 70th anniversary of the opening of the Four-Level Interchange, an engineering marvel, loved by few, loathed by many, and a daily source of stress for at least one person.
Somebody probably has calculated this. But it isn’t me.
I did this once. It wasn’t nearly as much fun as I thought it would be. Do not recommend.
This still happens today, most notably, for me, when you go from the 134 West to the 101 South or the 101 North to the 134 East.
The freeways still all have names. But no one likes to use them anymore. I grew up with them and still use them from time to time. But the numbers seem to have won the battle for popularity and few things cause more fear in locals her than saying “I have to drive the 405 during the evening rush hour through the Westside.”