Arroyo Seco Parkway, Los Angeles to Pasadena, Los Angeles, Los Angeles County, CA

Significance: The Arroyo Seco Parkway (Pasadena Freeway) was the first divided-lane, high-speed, limited-access road in the urban western United States and the first stretch of road for what would become the extensive Los Angeles freeway network. The approximately six-mile initial stage of the 8.2-mile roadway, completed in 1940, was envisioned as both a scenic road traversing the Arroyo and a vital traffic conduit linking the expanding cities of Pasadena and Los Angeles. Engineers and planners attempted to blend landscaping and native plants into the overall design while implementing safety features appropriate for high-speed travel. Construction proceeded alongside the installation of the federally assisted Arroyo Seco Flood Control Channel, necessary to ameliorate seasonal flooding. As road construction proceeded southward towards downtown Los Angeles in the early 1940s, the road began to more closely resemble a high-speed freeway. As a prominent example of the evolution from recreational parkways to more utilitarian high-speed freeways, the Arroyo Seco Parkway marks an important stage in the history of American transportation engineering. Unprocessed Field note material exists for this structure: N735 Survey number: HAER CA-265 Building/structure dates: 1938-1953 Initial Construction