Автомагистраль 210 в Калифорнии: Маршрут и особенности

Interstate and state highway in California

I 210's western terminus is at its junction with I 5, near the Sylmar district of Los Angeles. From that point, the freeway's alignment is generally diagonal as it heads southeast through the northeastern San Fernando Valley and the Crescenta Valley. After leaving Los Angeles, it enters northern Glendale and then La Cañada Flintridge where it meets with the Glendale Freeway and Angeles Crest Highway portions of SR 2 before turning due south towards the junction with SR 134) in Pasadena. At this interchange, the Foothill Freeway shifts its alignment and direction, becoming an east–west freeway. From the north, the primary through lanes of I 210 become the unsigned northern stub of unfinished I 710, while from the east, the through lanes of the Ventura Freeway become I 210 as the Ventura Freeway reaches its official eastern terminus. After intersecting the northern terminus of I 605, I 210 then continues east to SR 57 in Glendora. Heading east from the SR 57 interchange until its eastern terminus at I 10 in Redlands, Route 210 is signed as a state route. Portions of the Los Angeles County Metropolitan Transportation Authority's (Metro) light rail A Line runs in the median strip of I 210 from Pasadena to Arcadia, serving three stations at , , and
SR 210 presently has two distinct segments. The western segment consists of newer freeway, beginning at the east end of I 210 near San Dimas. SR 210 extends eastward, eventually paralleling Highland Avenue, as it continues through Fontana. It intersects I 15, an artery between Southern California and Nevada, about 10 mile (16 km) before it meets with I 215 in San Bernardino. The segment east of I 215 is the former alignment of SR 30. This segment extends eastward to junctions with I 215, SR 259, SR 18, and SR 330 in Highland. SR 210 then curves southward and ends in a junction with I 10 in Redlands. Route 210 is part of the California Freeway and Expressway System, and is part of the National Highway System, a network of highways that are considered important to the country's economy, defense, and mobility by the Federal Highway Administration. Route 210 is eligible for the State Scenic Highway System, but it is not officially designated as a scenic highway by the California Department of Transportation (CalTrans). Route 210 from Route 5 to Route 10 in Redlands is known as the Foothill Freeway, as named by Senate Concurrent Resolution 29, Chapter 128 in 1991.

The Glendora Curve is the former colloquial name for the interchange between what is now SR 57 and the Foothill Freeway, I 210. The "curve" refers to the I 210 freeway as it turned south in an almost 90 degree angle in the city of Glendora. Prior to 2002, this "curve" was entirely part of I 210, as it continued south to its former eastern terminus at the Kellogg Interchange at the junctions of the Chino Valley Freeway, SR 71, the San Bernardino Freeway, I 10, and SR 57. Once the I 210 was extended eastward from the Glendora Curve, the portion of I 210 south of the Glendora Curve was transferred to SR 57 and the name Glendora Curve fell out of popular use.

Construction began on the Foothill Freeway in 1958. The first section, starting at the eastern end of Foothill Boulevard in what is now La Cañada Flintridge, and going across the Arroyo Seco near Devil's Gate Dam to Canada Avenue in Pasadena, was opened in 1966; it was then signed as SR 118. This section was bypassed by the next stage of construction. The section going northwest from Pasadena through La Canada Flintridge to the junction with I 5 in Sylmar was built in several stages between 1971 and 1977. The first section to open was between Ocean View Boulevard and Lowell Avenue in La Crescenta, in July 1972, followed in November by the section between Berkshire Avenue and Ocean View in La Cañada Flintridge. The section of freeway in Sylmar, California, that was intended to open first (between I 5 and Maclay Avenue) was damaged by the 1971 Sylmar Earthquake, and the opening was delayed until repairs could be completed in 1973. In the Pasadena, California, section, a bridge span traversing the Arroyo Seco collapsed during construction on October 17, 1972, killing six workers, and as a result, the northbound section through Pasadena was not fully opened until 1974. The last section in the San Fernando Valley to be completed was between Highway 118 in Lake View Terrace, and Lowell Avenue in La Crescenta. While this section was largely completed by 1976, the portion between Sunland Boulevard and Wheatland Avenue (traversing the Tujunga Wash) was not fully completed until 1981. From 1976 to 1980, the uncompleted section of I 210 (notably near the interchange with Highway 118, near the Paxton Street exit) was rented by MGM Television for the filming of the television series CHiPs. In 1968, the Atchison, Topeka and Santa Fe Railway depot at Santa Anita, a historic structure built in 1890, was moved to the Los Angeles County Arboretum and Botanic Garden to make way for a section of the freeway passing through Arcadia. Construction of the freeway through Pasadena and Arcadia prompted the realignment and relocation of the railroad's mainline to the freeway's median, with the former mainline trackage between Sierra Bonita and Kinneloa avenues in Pasadena becoming an industrial spur accessed via an underpass below the freeway's eastbound lanes. The "Pasadena" section from SR 134 to Rosemead Boulevard was completed in 1976, while the section from Arcadia, California to the Kellogg Interchange with I 10 at Pomona had been previously completed in 1971. During the renumbering of California routes, LRN 190 was split into two different routes. The western portion, between I 210 in San Dimas and Highland became SR 30. The eastern portion, between SR 38 in Redlands and Highland was combined with LRN 207 (currently SR 330) to form SR 106. In 1972, the northern portion of SR 106, between SR 30 and SR 18 would be renumbered SR 330. The southern portion, between SR 30 and I 10 (SR 106 was moved to I 10 in 1965) was combined with SR 30. Initial freeway construction started in 1968, and constructed the freeway between SR 259 and Cedar Street in San Bernardino. Construction continued east in 1971, which brought the freeway just west of SR 330. Construction did not resume until 1989 which extended the freeway west to I 215. The last phase of construction started in 1992, which connected the route south to I 10. In 1968, the state requested that SR 30 be incorporated into the Interstate system, but was declined. When the Foothill Freeway mainline was completed in 2007, exit 74 had only four of its six ramps built, missing movements from SR 210 eastbound to I 215 southbound and from I 215 northbound to SR 210 westbound. The flyover plans for these moves had to be recast to address potential soil liquefaction in the event of rupture of existing or undiscovered faults in the area during an earthquake; this project was separated from the main 210 project to avoid delaying the latter. Completion of exit 74 was also tied to the widening of I 215 in the area. The flyover from northbound I 215 to westbound SR 210 opened on December 22, 2011, while the eastbound SR 210 to southbound I 215 opened on July 23, 2012, thus completing the interchange.

Caltrans District 8, in cooperation with the cities of Highland and San Bernardino and the San Manuel Band of Mission Indians, is currently evaluating ways to improve mobility and connectivity to the freeway at and near the Highland Avenue interchange, including a proposal to construct a new interchange to the east at Victoria Avenue. The Fair Oaks Avenue South exit in Pasadena is also being moved to not share an exit with the Northbound 210.