The
Los Angeles County Board of Supervisors decided in mid-1916, at the urging of the Harbor Truck Highway Association (formed mid-1914), to build a Harbor Truck Boulevard stretching about between
Los Angeles and
Compton, intended to be used by
trucks to the
Port of Los Angeles at
San Pedro. After that portion was completed, an extension to
Wilmington was opened on February 2, 1924, resulting in a completely independent truck route to the port. This roadway, which lay about halfway between Wilmington Avenue and
Long Beach Boulevard, extended the existing Alameda Street, which ran along—to
Slauson Avenue—and then west of the
Southern Pacific Railroad's
San Pedro Branch to Oris Street, the north limit of Compton. The truck boulevard continued along the west side to Dominguez Street (lying between the SP's San Pedro Branch and
Pacific Electric Railway's
Dominguez Line beyond Dominguez Junction), and crossed there to the east side for the rest of the route to Anaheim Street in Wilmington. There trucks could turn east and south to
Terminal Island via Henry Ford Avenue, or continue southwest through Wilmington to San Pedro. The highway soon came to be known as Alameda Street all the way to Wilmington. It did not become a state highway; instead the state took over
Figueroa Street (
SR 11) to the west and
Atlantic Avenue (
SR 15) to the east. Plans for
freeways in Los Angeles County evolved from a 1937
Automobile Club of Southern California plan, which was modified by the city's
Transportation Engineering Board (TEB) in 1939. The former included a single freeway connecting Los Angeles to Long Beach, beginning at
Pasadena and heading south-southwest to
Lynwood, then paralleling Long Beach Boulevard to Long Beach. The TEB's plan shifted this route farther east to near the present
Long Beach Freeway, while keeping the route near Long Beach Boulevard as a second freeway leaving the
Ramona Parkway (San Bernardino Freeway) east of downtown and heading south near Alameda Street and Long Beach Boulevard to Long Beach. This second freeway came to be known as the Long Beach Parkway or Alamitos Parkway, and connected in north Long Beach with a
Terminal Island Freeway southwest to
Terminal Island. Because the
Long Beach Naval Shipyard was located on the island, the
U.S. Navy paid for the construction of the $14 million freeway from the island to Willow Street, including the $5.3 million
Schuyler Heim Lift Bridge. Construction began in early 1946, and the completed link was dedicated on January 10, 1948, replacing the older
Henry Ford Bridge. Early plans also included a north–south freeway on each side of the
Los Angeles Central Business District, splitting at the merge of the
Harbor Parkway (Harbor Freeway) and
Venice Parkway northeast of the
University of Southern California, and rejoining at the split between the
Arroyo Seco Parkway (Pasadena Freeway) and
Riverside Parkway south of
Dodger Stadium. the latter later became part of the Harbor Parkway, while the former remained as a separate route roughly along
Main Street. The
Los Angeles City Planning Commission approved a revised master plan in mid-1955, based on various studied that had been made. A new Industrial Freeway replaced the Terminal Island Freeway and Alamitos Parkway between Terminal Island and downtown Los Angeles, where it then continued north along the former East By-Pass (which was not kept south of the
Santa Monica Freeway) and the southern part of the Riverside Parkway to the interchange of the
Glendale Freeway and
Golden State Freeway (which had replaced the rest of the Riverside Parkway). The Industrial Freeway south of the Santa Monica Freeway became Route 270 in 1959, but the ex-Riverside Parkway piece north of the Arroyo Seco Parkway never became a state highway. In the
1964 renumbering, the Industrial Freeway became Route 47, and the former East By-Pass became Route 241. The latter was deleted the next year, and the former was extended west from its south end on Terminal Island to
San Pedro, replacing part of
SR 7, which was truncated to
SR 1 in
Long Beach at the same time. (
I-710, which later replaced SR 7, has since been re-extended to SR 47 on Terminal Island.) This extension, which had been added to the state highway system in 1949 as part of
Route 231, included the 1963
Vincent Thomas Bridge. Construction on the $5.8 million freeway link from that bridge west to the
Harbor Freeway in San Pedro—officially the Seaside Freeway, but called an extension of the Harbor Freeway by the media—began in March 1968, and it was dedicated on July 9, 1970. The two parts of SR 47 were, and still are, connected by the Los Angeles-maintained Seaside Avenue and Long Beach-maintained Ocean Boulevard. (A freeway upgrade of the latter was completed in June 2007, but
traffic signals remain on the former and on the ramps connecting Ocean Boulevard with the Terminal Island Freeway.) Early maps show that the Terminal Island Freeway was to extend north to the
Long Beach Freeway (
I-710) near the
San Diego Freeway (
I-405), but the location for SR 47 adopted by the
California Highway Commission on January 22, 1969 led northwest from the Terminal Island Freeway's end at Carson Street to I-405 near Alameda Street, and then paralleled that street into Los Angeles. A 1982 state law specified that SR 47 shall use Henry Ford Avenue and Alameda Street between the Heim Bridge and the
Redondo Beach Freeway (
SR 91), rather than the adopted alignment to the east, and in 1984 the legislature created
State Route 103 to replace the former alignment on the Terminal Island Freeway between SR 47 and the
Pacific Coast Highway (
SR 1). Due to the cancellation of the Industrial Freeway and planned port expansions, the
Alameda Corridor project was created, including an improved rail line and a widening of Alameda Street from four to six lanes south of SR 91. Alameda Street was rebuilt for the project, with
grade separations at most major streets south of SR 91, and is now signed as part of SR 47 there, but remains mostly four lanes. As part of a project to replace the Heim Bridge,
Caltrans and the
Alameda Corridor Transportation Authority plan to improve the connection near the south end of Alameda Street, possibly by building a new
expressway replacement for SR 47 south of SR 1, or by extending SR 103 northwest via the originally-planned alignment to Alameda Street south of I-405. ==Major intersections==