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California Freeways: Still Seismically Unsafe

by William P. McGowan on Feb 19, 1997

Three years ago, the Northridge earthquake showed us Californians that we live in a dangerous place. The quake took lives, destroyed houses, and, most emblematic of all, toppled many of our freeways.        

As citizens of the Golden State, we live with the knowledge that the ‘Big One’ is still due. Yet despite the warnings, we are woefully unprepared for the next major earthquake. Nowhere is this unpreparedness more striking than in the state’s transportation system.        

Six years ago, I wrote an article that sought to explain why ‘earthquake safe’ freeways collapsed during the 1989 Loma Prieta earthquake. I found that most of our freeways were no safer in 1991 than they were twenty years earlier.  Despite reassurances, the fact remains that the seismic retrofit program has produced more political benefits than structural ones.

The seismic retrofit program began in 1972 when the San Fernando Valley earthquake toppled dozens of newly constructed freeways. After the quake, engineers discovered that practically every freeway overpass and bridge in the state was at risk of collapse. Nothing besides gravity was holding roadbeds to their support piers. While older structures could be ‘retrofitted’ with cables to keep roadbeds from falling off their supports, the only way to make freeways ‘seismically safe’ was to replace them entirely. The seismic retrofit project was conceived as a two-stage process: retrofit and rebuild.

The gas crises and stagflation of the 1970s changed the politics of transportation finance. Seismic safety, once a hot political issue, receded in relevance. Plans to rebuild freeways fell by the wayside. Underfunded and undervalued, the seismic program was still incomplete almost two decades later when Loma Prieta struck and a section of Interstate 880 known as the “Cypress Structure” collapsed, killing sixty-four commuters.

Unlike most California freeways in 1989, the Cypress structure had been retrofitted. Its collapse showed that California still needed to embark on the much more expensive and time-consuming process of rebuilding its freeways. By 1990, however, the cost of reconstruction was no longer in the millions but in the trillions.  As engineers investigated the seismic safety of freeway structures throughout the state, the scope of the project expanded dramatically. In 1987 CalTrans estimated that every mile of freeway in the state contained at least one structure needing reinforcement or reconstruction. Neither the state nor the federal government had the funds to rebuild this many structures.

Recognizing this, politicians repackaged retrofit as a long-term solution and sold it to the voters in the form of two seismic safety bond initiatives. With the passage of Propositions 111 and 113, Californians were again lulled into believing that government was making its freeways earthquake safe. In fact, less and less was being done.

Today, money set aside for freeway reconstruction is being spent on programs that have nothing to do with transportation. While Republican administrations sequestered transportation moneys to make budget deficits look smaller, the Clinton Administration has done the most damage by convincing Congress to allow gas-tax revenues to be spent on social programs that do nothing for our infrastructure. Since 1993, money originally ear-marked for highway reconstruction projects has been spent instead on programs such as Medicare, Medicaid, and Social Security.

California voters were sold a seismic safety program that is structurally dubious. The recent anniversary of the Northridge earthquake should serve to remind us that the only seismically-safe freeway is a new freeway.


William P. McGowan is a doctoral candidate in history at the University of California at Santa Barbara. He is author of "Fault-Lines: Seismic Safety and the Changing Political Economy of California's Transportation System," an article in "California History" (Summer 1993) that was adopted by CalTrans as part of its official report to Congress on the Loma Prieta Earthquake.