Cypress Street Viaduct

Cypress Street Viaduct
Cypress Freeway, Nimitz Freeway
Route of the viaduct in relation to modern roads
Route information
Maintained by Caltrans
Length	1.78 mi (2.86 km)
Existed	June 11, 1957–October 17, 1989
Component highways	SR 17 (entire length, 1957–1984) I-880 (entire length, 1984–1989)
NHS	Entire route
Major junctions
North end	I-80 / I-580 in Oakland
South end	Market Street at 7th Street in Oakland
Location
Country	United States
State	California
Counties	Alameda
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future State highways in California Interstate US State Scenic History Pre‑1964 Unconstructed Deleted Freeways

The Cypress Street Viaduct, often referred to as the Cypress Structure or the Cypress Freeway, was a 1.6-mile-long (2.5 km), raised two-deck, multi-lane (four lanes per tier) freeway constructed of reinforced concrete that was originally part of the Nimitz Freeway (State Route 17, and later, Interstate 880) in Oakland, California, United States.

It replaced an earlier single-deck viaduct constructed in the 1930s as one of the approaches to the San Francisco–Oakland Bay Bridge. It was located along Cypress Street between 7th Street and Interstate 80 in the West Oakland neighborhood.

It officially opened to traffic on June 11, 1957, and was in use until October 17, 1989. At approximately 5:04 p.m. that day, a magnitude 6.9 earthquake struck the Bay Area, resulting in a large portion of the freeway's upper deck collapsing onto the lower deck. The collapse killed 42 people and resulted in the subsequent demolition of the structure.^[1]

The Cypress Freeway Memorial Park is located in Oakland, at 14th Street and Mandela Parkway.