The Santa Monica Freeway is the westernmost segment of Interstate 10, beginning at the western terminus of I-10 at the Pacific Coast Highway in Santa Monica, California and ending southeast of downtown Los Angeles at the famous East Los Angeles Interchange. (I-10 continues as 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 (2 local, 5 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 8 and 10 lanes in width.
While the construction of the Century Freeway several miles to the south eased traffic congestion to a considerable extent 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).
The Santa Monica Freeway is the freeway for which ground is being broken in the film L.A. Confidential. It is also remembered for a partial collapse west of downtown (at the large interchange with La Brea Avenue and Washington Boulevard) after the 1994 Northridge Earthquake. The title of punk rock legends The Minutemen's 1984 double album, Double Nickels on the Dime, is trucker slang referring to the freeway's then-current speed limit of 55 miles per hour.
Communities along the length of the Santa Monica Freeway include:
Freeways intersecting the Santa Monica Freeway include: