Proposals to replace the Alaskan Way Viaduct date back to the 1970s during attempts to revitalize the city 's waterfront for tourist and recreation rather than traditional industrial uses . After a similar double-decker freeway , the Cypress Street Viaduct in Oakland , California , collapsed during the Loma Prieta earthquake in 1989 and killed 42 people , calls to replace the viaduct intensified due to the realized earthquake risk . A 1995 study commissioned by the state government after the Kobe earthquake found vulnerabilities in the Alaskan Way Viaduct 's design that could cause severe damage and collapse during a major earthquake , along with liquefaction risks due to the underlying reclaimed land that the highway was built on . The study estimated that it would cost $ 118 million ( equivalent to $ in dollars ) to demolish the viaduct , $ 344 million ( equivalent to $ in dollars ) to retrofit the structure for earthquake resistance , and $ 530 million ( equivalent to $ in dollars ) to build a new elevated freeway to replace it ; other options included replacing the freeway with a tunnel or a surface boulevard with public transit on Alaskan Way , similar to San Francisco 's Embarcadero
Loma Prieta earthquake
1989 Loma Prieta earthquake
Washington State Route 99