This route is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System.

Route description

Santa Monica Freeway

Interstate 10 begins in the city of Santa Monica when State Route 1 turns into a freeway and heads east. SR 1 exits onto Lincoln Boulevard and heads south while I-10 continues east. Soon after it enters the city of Los Angeles, I-10 has a four-level interchange with Interstate 405. Interstate 10 then continues through Jefferson Park into downtown Los Angeles. On the western edge of downtown, I-10 has an interchange with Interstate 110 to the south and State Route 110 to the north. I-10 then travels along the southern edge of downtown to the East Los Angeles Interchange.

At the East Los Angeles Interchange, State Route 60 diverges east towards Riverside and Pomona. I-10 then turns north, running concurrently with Interstate 5 for a few miles. Then, Interstate 10 heads east and merges with the traffic from the spur to US 101 onto the San Bernardino Freeway.

The section between the Harbor and San Diego freeways is also signed as the Rosa Parks Freeway. The freeway is signed as the Christopher Columbus Transcontinental Highway in Santa Monica. The freeway is 14 lanes wide (two local, five express in each direction) from the Harbor Freeway interchange to the Arlington Avenue offramp; most of these lanes are full at peak travel times (even on Saturdays). The remainder of the freeway varies between eight and 10 lanes in width. The whole freeway was opened in 1964.

While the construction of the Century Freeway several miles to the south eased traffic congestion to a considerable amount by creating an alternate route from downtown to Los Angeles International Airport, the Santa Monica Freeway is still one of the busiest freeways in the world. All three freeway-to-freeway interchanges along its length are notorious for their congestion and are routinely ranked among the top 10 most congested spots in the United States.

Due to the high traffic volume, car accidents are so common that Caltrans has constructed special Accident Investigation Sites separated from the freeway by fences. These enable the California Highway Patrol to quickly clear accidents from the through traffic lanes, and the fences reduce congestion by preventing rubbernecking (where cars slow to watch the accident investigation).

Spur to US 101

This road is signed only for the roads it feeds into - US 101 north westbound and I-10 east eastbound. It has no interchanges except its ends. The exit numbers for I-10 is to follow the signed route of I-10 west along with I-5 south, but one exit on Route 10 - the eastbound for State Street and Soto Street before it merges onto I-10 eastbound - is numbered (as exit 19).

There is no access on this spur from Route 10 eastbound to I-5 northbound.

San Bernardino Freeway

East of Interstate 710, I-10 continues through Monterey Park, Alhambra, Rosemead, San Gabriel, El Monte, and Baldwin Park before intersecting with Interstate 605. It then travles through West Covina and Covina before heading up Kellogg Hill into San Dimas, where I-10 intersects with State Route 57 (formerly part of Interstate 210) and State Route 71. I-10 then heads east through Pomona and Claremont into San Bernardino County.

In San Bernardino County, Interstate 10 travels through Montclair, Upland, and Ontario, providing access to Ontario International Airport. I-10 then has a four level interchange with Interstate 15 before traveling through Fontana, Rialto, and Colton. I-10 then intersects with Interstate 215 before briefly entering San Bernadino city proper and traveling through Loma Linda and Redlands. In Redlands, I-10 intersects with the State Route 210 freeway (currently signed as SR-30) and with State Route 38 before entering Yucaipa and eventually Riverside County.

Portions in Palm Deserts

Notably, I-10 westbound is usually signed as towards San Bernardino and/or Los Angeles in the Mojave Desert. Eastbound, in San Gorgonio Pass, the signage bizarrely indicates "Indio, Other Desert Cities", and indicates "Blythe" after Indio - the first sign for Phoenix does not occur until after the SR 86S exit in Coachella.

The Santa Monica Freeway is Route 10 from Route 1 to Route 5, as named by the State Highway Commission on April 25 1957.

The Rosa Parks Freeway is Route 10 from Route 110 to Route 405, as named by Assembly Concurrent Resolution 134, Chapter 2 in 2002.

History

The route from Indio via Mecca to the Arizona state line near Blythe was defined in 1919 as pre-1964 Legislative Route 64. (Later extensions took LR 64 west along present State Route 74; a 1931 cutoff bypassed Mecca to the north.) LR 26 was extended west from San Bernardino to Los Angeles in 1931, running along an alignment south of the existing US 66/US 99. Neither of these was a signed route until ca. 1932, when U.S. Route 60 was extended west from Arizona to Los Angeles, running along LR 64 to Indio, LR 26 (with US 99) to Beaumont, pre-1964 Legislative Route 19 to Pomona, and LR 26 to Los Angeles. (The original alignment of LR 26 ran roughly where State Route 60 now is west of Pomona, but an alignment close to present I-10 opened ca. 1934.

Thus, in 1931, what is now I-10 east of Los Angeles had been defined as LR 26 from Los Angeles to Indio and LR 64 from Indio to Arizona. It was signed as US 99 from San Bernardino to Indio, and US 60 came along ca. 1932 from Los Angeles to Pomona and from Beaumont to Arizona. U.S. Route 70 was extended west from Arizona ca. 1936 along the whole route to Los Angeles, and, between 1933 and 1942, US 99 moved from US 66 to present I-10 between San Bernardino and Los Angeles, forming a three-way concurrency between Pomona and Los Angeles. Old alignments and names include Valley Boulevard, Ramona Boulevard and Garvey Avenue.

The route east from Los Angeles was added to the Interstate Highway System on August 7, 1947. It was assigned the I-10 number on August 14, 1957, and the short piece west of I-5 was approved as I-110 on November 10, 1958. By then, most if not all of the San Bernardino Freeway had been completed, and I-10 was signed along the existing freeway along with US 70, US 99, and part of US 60. Those three routes were all removed in the 1964 renumbering, leaving only I-10.

The part west of downtown Los Angeles was pre-1964 Legislative Route 173, defined in 1933 from Santa Monica to downtown Los Angeles. It was signed as State Route 26 by 1942, running along Olympic Boulevard. It was later replaced by the Santa Monica Freeway, and added to the Interstate Highway System on September 15, 1955. It too was assigned the I-10 number on August 14, 1957. It was completed ca. 1964, and became I-10 in the 1964 renumbering.

Portions of the Santa Monica Freeway going over La Cienega Boulevard collapsed after the Northridge earthquake on January 17, 1994..

Exit list

Note: Except where prefixed with a letter, postmiles were measured in 1964, based on the alignment as it existed at that time, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.

References

External links

• California @ WestCoastRoads - Interstate 10
• California Highways: I-10
• Cal-NExUS: Route 10 West
• Cal-NExUS: Route 10 East