early Arroyo Seco Parkway, Los Angeles

Previously known as the Pasadena Freeway, this was the first freeway in California and the western US. It connects LA with Pasadena alongside the Arroyo Seco seasonal river. Although ample when built, it is now regarded as narrow and outdated. A 1953 extension brought the south end to the Four Level Interchange in downtown LA and a connection with the rest of the freeway system. The road remains largely as it was when opened although the plants in its median are now mostly concrete barriers, and it has the designation State Route 110 and not the historic US Route 66.