;
Pacific Electric Railway trolleys ran down the center median of this freeway until 1952 The freeway runs from the
Four Level Interchange in downtown Los Angeles to the
Golden State Freeway in the
Sun Valley district of Los Angeles in the
San Fernando Valley. From the Four Level Interchange to its intersection with the
Ventura Freeway in the southeastern San Fernando Valley (also known as the
Hollywood Split), the freeway is signed as part of
U.S. Route 101. Afterwards, it is signed as State Route 170 until its northern terminus at
Interstate 5. The intersection of the Hollywood,
Santa Ana, and
Harbor freeways and the
Arroyo Seco Parkway, known as the
Four Level Interchange, is one of the major landmarks in Los Angeles and a symbol of the city's post-
World War II development.
State Route 170 Route 170 is defined as follows in section 470, subsection (a) of the
California Streets and Highways Code: Route 170 is from
Route 101 near
Riverside Drive to
Route 5 near
Tujunga Wash. In addition to the above, the original 1963 definition of Route 170 included "
Route 405 near
Inglewood to Route 101 in Los Angeles" in a separate subdivision. This was defined in anticipation of the
Laurel Canyon Freeway, which never came to fruition. In 1970, the definition was amended to subdivide the portion south of US 101 as "(a)
Los Angeles International Airport to
Route 90." and "(b)
Route 2 to Route 101 in Los Angeles," deleting the segment between SR 2 and an extension of SR 90 that was never constructed. Subdivision (b) would run along
Highland Avenue in
Hollywood. In 2015, the state relinquished Highland Avenue to the city of Los Angeles, and the legislature amended the definition to reflect that as well as remove the final unconstructed freeway segment. However, subdivision (b) was also modified to require the city to still "maintain signs directing motorists to the continuation of Route 170". and are part of the
National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the
Federal Highway Administration. As of 2018, Caltrans is planning to add soundwalls to SR 170 in both directions between
Sherman Way and the
Hollywood Split. There are currently some neighborhoods located near the freeway, which cause noise pollution. Now that soundwalls are in place, it can reduce the noise and reduces smog. ==History==