Photo above and others linked to in this post courtesy of the U.S.C. Digital Archive.
Today, this is the downtown section of the Pasadena Freeway (Interstate 110). In 1959, though, when this photo was taken, it was the northernmost section of the Harbor Freeway (California State Highway 11), and this is how I first remember it.
I like this photo primarily for its composition, but also because it gives a great close-up view of what an old L.A. freeway looked like. Mom hated the Harbor Freeway, though, so we rarely took this route, but I still have vivid recollections of the eastern San Bernardino Freeway (U.S. 99 then/I-10 now) in the late '50s, and our hometown stretch looked exactly like this (minus the fancy planters in the center divider).
The freeways were quite different back then. For one thing, all of the exit and informational signs on the original freeways were made of porcelain steel, and had white letters on a black background, like the one here that says "Downtown." The smaller informational signs at the roadside had reflectors in the letters so they could be read at night, but the large signs were illuminated by lights, much like a billboard. (Here's another view of the Downtown Harbor, showing some nice examples of the larger black-and-white signage.) The first time I remember seeing the green freeway signs of today was when the first stretch of the Santa Monica Freeway opened in 1961.
To me, though, the most remarkable feature of the early freeways was the complete absence of any kind of crash barrier in the median strip. This plus the fact that seat belts were still a relatively rare innovation in the 1950s – well, it's no wonder many people back then thought that driving on a freeway was literally taking your life in your hands. Note that the curb isn't even sharply angled to keep a tire from straying into the dividing strip. It's easy to imagine how someone in the fast lane could take their eyes off the road for only a second or two, drift to the left a few inches, then suddenly find themselves facing an imminent, fatal head-on collision. (Here is a photo of the Pasadena Freeway in 1958, showing a similar lack of any effective barrier in the median.)
The first built-in barrier I can recall was again on the new downtown Santa Monica in 1961, which had chain-link fencing in the center divider. (!!!) Oh yeah, I felt A LOT safer then! It was only after they started using chain-link, though, that you could see just how often cars strayed into the median (and how pathetic the chain-link was at preventing cross-overs). Really, that fencing looked like a war zone in places. And it must have been a genuine pain to repair, too, as the metal posts were seated directly into the asphalt of the center divide.
One thing about the freeways that's stayed the same over the last 50 years is the traffic congestion. Everything else in L.A. may change, but traffic jams there really are forever.