How Freeways Shaped the San Francisco Bay Area’s Growth

Image 1: Alemany Interchange (Image from SFCTA)

Freeways have been a quintessential part of American infrastructure changing the ways we live and operate throughout our daily lives. They did not just serve as a car transporter, rather they helped fuel a development pattern called suburban expansionism and sprawl. The (SF) Bay Area is a perfect example of seeing how these concrete motorways changed city growth. With the completion of I-580 and I-680 highways, people were able to be farther away from their workplaces and still have a medium to commute to the centers of the region. Highways defined the Bay Area through a variety of different ways that we will explore.

The 1950s Bay Area consisted of a series of urban-cores along with smaller agricultural communities. Most of the population were centered in or in close proximity to the central districts of cities like San Jose, San Francisco and Oakland. Since population was not spread out as much, street-cars and ferry systems were what most of the Bay Area used for transportation. The current suburban cities were mostly agricultural centered economies back then.

Post World-War 2, the development of highways starts to be seen across the nation. The Department of Transportation funded the Interstate Highway System which led to the development of highways in the Bay Area. Counties in the region partnered with CalTrans in order to route these motorways through underdeveloped valleys and the effects can be seen in many counties such as Contra Costa County. Here, the population spiked by 231% from 1950 to 1970 (U.S. Census Bureau). 

As mentioned previously, I-580 and I-680 would be the most influential of the highways. The 580 route connected the East Bay all the way to the Central Valley and the 680 connected large parts of the San Ramon Valley to develop into master-planned suburbs. These highways led to huge influxes of population in these previously sparsely populated regions. The I-680 reported around 150,000 vehicles per day at certain segments (Caltrans Traffic Census Program). The development of living areas changed to being focused on connected people to these main freeways.

Despite maintaining large offices and companies in the urban cores of the region, Bay Area also saw companies follow the new population centers. One such example is Bishop Ranch, which is one of Northern California’s largest office parks and can be seen all throughout the San Ramon Valley. Large malls such as Stoneridge and the, now fading, Sunvalley opened up near highway intersections as retail chased freeway development. These highways also led to automobile-first neighborhoods being developed throughout the Bay, notably with wide arterial roads, spacious parking lots, and separated land-use. 

Many changes could also be observed to the environment and connectivity of the Bay Area. Heavy car-dependancy has occurred throughout much of the Bay Area as freeways incentivized driving as the easiest option. Along with this, heavy traffic is present throughout much of these routes, with I-680 and I-580 ranked among the top 10 most congested corridors in Northern California (MTC Vital Signs Congestion Data). With a large increase in car usage and congestion came a sizable amount of pollution and emissions. Finally, urban fragmentation occurred as cities were physically split from each other and walking plummeted as options decreased.

So what is being done now to offset some of these issues that freeways have brought. Cities such as San Ramon, Walnut Creek, Dublin, Pleasanton and Antioch have been aiming to develop and push for more mixed-used, walkable centers. Many new projects, such as the Iron Horse trail overcrossing analysed in another blog, helped increase walkability again by safekeeping pedestrians. Protected bike-lanes in many cities also add more alternatives to automobiles, especially for shorter commutes. TOD, or Transit Oriented Development, is also a new policy being implemented to develop near locations such as BART subway stations. Through the MTC TOD Impact Survey, researchers found that TOD residents drove 40% to 60% less than the average Bay Area suburban resident.

In conclusion, the freeway was essential in developing the Bay Area into the region it is today. It unlocked a new level of growth, but also led to traffic and other sprawl-related consequences. Understanding the influence of these corridors is key in helping cities transition into safer and more connected urban development. Many cities are researching ways in order to redesign their cities to make it walkable while still being able to use the freeway.