State Route 57

State Route 57
State	CA
Type	SR
Route	57
Length mi	48.5
Maint	Caltrans
Established	1964
Direction a	South
Terminus a	I‑5 in Santa Ana
Junction	SR 714 in Fullerton; SR 60 in Diamond Bar; I‑10 in Pomona
Direction b	North
Terminus b	SR 14 in Palmdale
Counties	Orange County, Los Angeles County

State Route 57 is a north–south highway in Southern California connecting the Orange County coastal plain with the San Gabriel Valley and the northern Los Angeles County Antelope Valley. The route serves as a major connector between I‑5, I‑10, SR 60, and SR 14, traversing urban centers such as Santa Ana, Anaheim, Fullerton, and Pomona. It forms part of the regional network used by commuters, freight haulers, and transit services including Metrolink and local bus operators.

Route description

The highway begins at a junction with I‑5 near Downtown Santa Ana and proceeds northward adjacent to Santa Ana River, passing landmarks like Angel Stadium of Anaheim, Anaheim Convention Center, and the industrial districts of Buena Park. In Fullerton the route interfaces with the Fullerton Transportation Center and parallels lines used by Metrolink Orange County Line, 91/Perris Valley Line, and freight corridors operated by Union Pacific Railroad and BNSF Railway. Continuing into the Puente Hills area, the highway intersects SR 60 near Diamond Bar and threads through the Pomona Valley, providing access to institutions such as Cal Poly Pomona, Fairplex, and the Pomona Fairgrounds. North of Pomona the route climbs the San Gabriel Mountains foothills, meeting I‑10 and proceeding toward the Antelope Valley where it terminates near Palmdale at SR 14. The corridor passes adjacent to parks like Yorba Regional Park and conservation areas such as Puente Hills Preserve.

History

The highway corridor follows older alignments used during the Spanish colonization of California and later California Gold Rush era routes that linked Los Angeles basin settlements with inland valleys. Early 20th‑century roadways including portions of the Lincoln Highway and state legislative routes were upgraded under efforts by the California Division of Highways and later Caltrans during the mid‑20th century. Major expansions occurred in the 1960s amid the construction of the Interstate Highway System and regional freeway projects shaped by planners from agencies like the Southern California Association of Governments and municipal governments of Anaheim, Fullerton, and Pomona. The freeway interchange nicknamed the "Orange Crush"—linking the route with I‑5, SR 22, and I‑405 in the Irvine‒Garden Grove vicinity—became a focal point of reconstruction projects in the 1990s and 2000s coordinated with funding measures such as Measure M and state transportation bonds.

Major intersections

Key junctions along the corridor include the southern terminus at I‑5 in Santa Ana; connections with SR 22 serving Garden Grove and Orange; the interchange with I‑405 near Anaheim; access to SR 60 near Diamond Bar and Pomona; the junction with I‑10 providing regional links to Los Angeles and San Bernardino; and the northern termination at SR 14 adjacent to Palmdale and the Antelope Valley California Museum. Interchanges also serve OCTA park‑and‑ride facilities and Metrolink stations.

Traffic and usage

The route is a primary commuter artery for workers traveling between Orange County suburbs and employment centers in Los Angeles County and the Inland Empire. Freight movements include trucks accessing intermodal facilities tied to Port of Long Beach and Port of Los Angeles, with traffic studies by agencies such as the California Department of Transportation and Metro documenting peak congestion at interchanges including the Orange Crush and the SR 60 junction. Peak hour volumes are influenced by events at Angel Stadium of Anaheim and conventions at the Anaheim Convention Center, while seasonal spikes occur during fairs at the Los Angeles County Fair and California State Fair‑adjacent venues. Safety analyses reference collision data compiled by Caltrans and local sheriff departments such as the Orange County Sheriff's Department and Los Angeles County Sheriff's Department.

Future plans and improvements

Planned improvements involve interchange reconstructions, auxiliary lane additions, and managed lanes projects promoted by regional planners from SCAG and funded in part through sales tax measures like Measure M and state transportation initiatives. Proposed projects under consideration include capacity upgrades near Fullerton to improve access to Cal State Fullerton, noise‑mitigation barriers adjacent to residential communities like Brea and La Mirada, and coordinated transit integration with Metrolink and OCTA to expand express bus services. Environmental reviews reference the California Environmental Quality Act and consultations with agencies including the California Department of Fish and Wildlife for habitat impacts in the Puente Hills and San Gabriel Mountains foothills.

Related designations and spur routes

The corridor intersects and overlays several numbered routes and special designations historically, including past legislative route numbers and auxiliary connectors such as spur ramps to SR 60 and short segments maintained as local arterials in municipalities like Diamond Bar and Pomona. Park‑and‑ride connections and bus‑only ramps link to services operated by OCTA, LA Metro, and regional carriers serving destinations including Ontario International Airport and John Wayne Airport. The corridor's role within the National Highway System and its inclusion in state freight plans underscore its strategic importance to CalSTA and regional mobility initiatives.

Category:California State Routes