Along with beaches, palm trees, and movie studios, the freeway is one of Southern California's trademarks. Perhaps no other urban areas in the world have embraced the automobile as passionately as have those of Los Angeles, Inland Empire, Orange County, and San Diego. Extensive freeway networks criss-cross the still fast-growing region, connecting urban centers with their suburbs and exurbs, as well as the areas of sprawling development between them. The popular Burt Bacharach/Hal David song, "Do You Know the Way to San Jose?", contains a line that for many sums up the status of automobile transit in the City of Angels: "L.A. is a great big freeway." Despite the recent construction of high-profile mass transit projects in the region, this line is just about as apt today as it was in the mid-1960s.
As in many American cities, Southern California freeways have names that are often distinct from the state or federal highway number that they are assigned. While Southern California residents idiomatically refer to freeways with the definite article, as "the [freeway number]" (e.g., the Santa Monica and San Bernardino freeways are known as "the 10," as they are segments of Interstate 10), traffic reporters, highway signs, and transportation planners usually refer to a freeway by its full, descriptive name.
Southern California's romance with the automobile owes in large part to resentment of the Southern Pacific Railroad's tight control over the region's commerce in the late 19th and early 20th centuries. During his successful campaign for governor in 1910, anti-Southern Pacific candidate Hiram Johnson traveled the state by car (no small feat at that time). In the minds of Southlanders, this associated the automobile with clean, progressive government, in stark contrast to the railroads' control over the corrupt governments of the Midwest and Northeast. While the Pacific Electric Railroad's famous "Red Car" streetcar lines were the axes of urbanization in the region during its period of spectacular growth in the 1920s and 1930s, the Red Car's unprofitability and limited capacity threatened to choke off the region's development. At the same time, a number of influential urban planners were advocating the construction of a network of what one widely-read book dubbed "Magic Motorways ," as the backbone of suburban development. These "greenbelt" advocates called for decentralized, automobile-oriented development as a means of remedying both urban overcrowding and declining rates of home ownership.
During World War II, transportation bottlenecks on Southern California railways (including the Pacific Electric) convinced many that if Southern California were to accommodate growth, it needed a completely new transportation system. The city of Los Angeles favored an upgraded rail transit system focused on its central city, like those being installed in the bombed-out cities of Europe under the Marshall Plan. However, the success of the Arroyo Seco Parkway, built between Los Angeles and Pasadena in 1940, convinced many that a system of similar roads could solve the region's transportation problems. Leaders of surrounding cities, such as Whittier, South Gate, Long Beach, and Pasadena, accordingly called for a web of freeways to connect the whole region, rather than funneling their residents out of their own downtowns and into that of Los Angeles. Pro-freeway sentiments prevailed, and by 1949 a comprehensive freeway plan for Los Angeles had been drawn up by Caltrans. San Diego soon followed suit, and by the early 1950s construction had begun on much of the region's freeway system.
The devastation of communities through which freeways had been routed (which stood in stark contrast to the prosperity of areas developed around the new routes) and the growing problem of air pollution served to dampen enthusiasm for freeways, and by the 1970s Caltrans abandoned many planned freeways in the face of significant political opposition. Growing enthusiasm for mass transit siphoned tax dollars away from freeway construction, and the California tax revolt of that same decade significantly reduced the resources available for infrastructure development. By 2004, only 61% of the freeway miles proposed in the 1954 master plan had been built. While many of these routes were geographically improbable (e.g. the Angeles Crest and Decker Freeways), the abandonment of routes such as the Laurel Canyon and Topanga Canyon Freeways combined with Caltrans' failure to complete routes such as the Long Beach and Glendale Freeways to create gaps and bottlenecks in the freeway system that caused ripple effects of congestion throughout the entire network. In response to the drying-up of funds from state government that followed in the wake of Proposition 13, Orange County--perhaps the biggest beneficiary of the freeway system--embarked on its own program of tollway construction in the 1980s using local funds, and began to apply local financing to freeway construction as well after the turn of the 21st century.
After a deep recession in the early 1990s caused by the collapse of the defense industry at the end of the Cold War, Southern California began to grow again in the latter part of the decade. As in the region's population surge in the 1920s and 1930s, most of the new arrivals were impoverished ex-farmers (albeit from Mexico this time around instead of Kansas and Oklahoma), and as in that period of growth, the region's infrastructure has had difficulty in keeping up. Even in the face of the state budget crisis of the early 2000s, plans have been drawn up to radically expand the region's transportation network to accommodate population growth that has already swelled the region's population to 17 million (as of the U.S. Census of 2000) and may see it grow to 25 or even 30 million in the coming decades. Environmentalist sentiments and the dearth of available land within a short drive of the region's urban centers will likely result in future development taking a pattern along the mass transit-oriented lines of the "smart growth" school's recommendations, but it is clear that freeways will continue to play an important, if not dominant, role in Southern California's transportation throughout the 21st century.
Despite the previously-mentioned impediments to freeway construction, and the pressing need to rebuild many freeways designed for far lower volumes of traffic than their current usage, Caltrans' portfolio of new freeway projects remains sizable. Notable projects (some of which may never come to pass) include:
- Extension of the California State Highway 710 (CA/SR-710), "Long Beach Freeway", to its originally planned terminus at Interstate 210 (I-210), "Foothill Freeway", in Pasadena, via a tunnel underneath the city of South Pasadena
- Construction of a High Desert Freeway, connecting the Antelope and Victor valleys in the Mojave Desert
- Extension of the California State Highway 2 (CA/SR-2), "Glendale Freeway", to the California State Highway 14 (CA/SR-14), "Antelope Valley Freeway", via a 40-mile long tunnel through the San Gabriel Mountains
- Construction of the Ted Williams Freeway, in northwestern San Diego
- Extension of the Interstate 15 (I-15), "Escondido Freeway", to Interstate 5 (I-5), near downtown San Diego
- Conversion of open-access portions of California State Highway 58 between Barstow and Tehachapi to Interstate highway standards, with the aim of extending Interstate 40 (I-40) from its current western terminus in Barstow at Interstate 15 (I-15) to Interstate 5 (I-5) in Buttonwillow
- Addition of high occupancy vehicle and high occupancy toll lanes to freeways currently lacking them
- Construction of lower-inclined alternate alignments on steep segments of freeway, to enable trucks to climb mountain passes more easily and speed up the flow of automobile traffic
- Construction of an additional freeway across the Santa Ana Mountains, to relieve congestion on the California State Highway 91(CA/SR-91) "Riverside Freeway" and provide a route between the Inland Empire and southern Orange County.
Many of the firsts of Southern California freeways
- First city to have stacked urban diamond freeway junction