A roundabout is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.
State Route 1 (SR 1) is a major north–south state highway that runs along most of the Pacific coastline of the U.S. state of California. At 656 miles (1,056 km), it is the longest state route in California, and the second-longest in the US after Montana Highway 200. SR 1 has several portions designated as either Pacific Coast Highway (PCH), Cabrillo Highway, Shoreline Highway, or Coast Highway. Its southern terminus is at Interstate 5 (I-5) near Dana Point in Orange County and its northern terminus is at U.S. Route 101 (US 101) near Leggett in Mendocino County. SR 1 also at times runs concurrently with US 101, most notably through a 54-mile (87 km) stretch in Ventura and Santa Barbara counties, and across the Golden Gate Bridge.
State Route 91 (SR 91) is a major east–west state highway in the U.S. state of California that serves several regions of the Greater Los Angeles urban area. A freeway throughout its entire length, it officially runs from Vermont Avenue in Gardena, just west of the junction with the Harbor Freeway, east to Riverside at the junction with the Pomona and Moreno Valley freeways.
State Route 55 (SR 55) is an 18-mile (30-km) long north–south state highway that passes through suburban Orange County in the U.S. state of California. The portion of the route built to freeway standards is known as the Costa Mesa Freeway. SR 55 runs between Via Lido south of Pacific Coast Highway in Newport Beach and the Riverside Freeway in Anaheim to the north, intersecting other major Orange County freeways such as SR 22, SR 73, and Interstate 405 (I-405).
State Route 22 is an east–west state highway in the U.S. state of California that serves southern Los Angeles County and northern Orange County. It runs between Pacific Coast Highway in Long Beach and the Costa Mesa Freeway in Orange by way of Garden Grove. The westernmost part of SR 22 runs along Long Beach's 7th Street. From West Garden Grove to its eastern terminus in Orange, it is known as the Garden Grove Freeway. It is one of the two principal east–west routes in Orange County.
Route 110, consisting of State Route 110 (SR 110) and Interstate 110 (I-110), is a state and auxiliary Interstate Highway in the Los Angeles metropolitan area of the US state of California. The entire route connects San Pedro and the Port of Los Angeles with Downtown Los Angeles and Pasadena. The southern segment from San Pedro to I-10 in downtown Los Angeles is signed as I-110, while the northern segment to Pasadena is signed as SR 110. The entire length of I-110, as well as SR 110 south of the Four Level Interchange with US Route 101 (US 101), is the Harbor Freeway, and SR 110 north from US 101 to Pasadena is the historic Arroyo Seco Parkway, the first freeway in the western United States.
Route 710, consisting of the non-contiguous segments of State Route 710 (SR 710) and Interstate 710 (I-710), is a major north–south state highway and auxiliary Interstate Highway in the Los Angeles metropolitan area of the U.S. state of California. Also called the Los Angeles River Freeway prior to November 18, 1954, the highway was initially planned to connect Long Beach and Pasadena, but a gap in the route exists from Alhambra to Pasadena through South Pasadena due to community opposition to its construction.
Interstate 405 (I-405) is a major north–south auxiliary Interstate Highway in Southern California. The entire route is known as the northern segment of the San Diego Freeway. I-405 is a bypass auxiliary route of I-5, running along the southern and western parts of the Greater Los Angeles urban area from Irvine in the south to near San Fernando in the north.
State Route 14 is a north–south state highway in the U.S. state of California that connects Los Angeles to the northern Mojave Desert. The southern portion of the highway is signed as the Antelope Valley Freeway. The route connects Interstate 5 on the border of the city of Santa Clarita to the north and the Los Angeles neighborhoods of Granada Hills and Sylmar to the south, with U.S. Route 395 (US 395) near Inyokern. Legislatively, the route extends south of I-5 to SR 1 in the Pacific Palisades area of Los Angeles; however, the portion south of the junction with I-5 has not been constructed. The southern part of the constructed route is a busy commuter freeway serving and connecting the cities of Santa Clarita, Palmdale, and Lancaster to the rest of the Greater Los Angeles area. The northern portion, from Vincent to US 395, is legislatively named the Aerospace Highway, as the highway serves Edwards Air Force Base, once one of the primary landing strips for NASA's Space Shuttle. This section is rural, following the line between the hot Mojave desert and the forming Sierra Nevada mountain range. Most of SR 14 is loosely paralleled by a main line of the Southern Pacific Railroad, used for the Antelope Valley Line of the Metrolink commuter rail system as well as a connection between Los Angeles and the Central Valley via Tehachapi Pass.
State Route 58 is a major east-west state highway in the U.S. state of California that runs across the Coast Ranges, the southern San Joaquin Valley, the Tehachapi Mountains, which border the southern Sierra Nevada, and the Mojave Desert. It runs between U.S. Route 101 near Santa Margarita and Interstate 15 in Barstow. It has junctions with Interstate 5 near Buttonwillow, State Route 99 in Bakersfield, State Route 202 in Tehachapi, State Route 14 near Mojave, and U.S. Route 395 at Kramer Junction. SR 58 also provides access to Edwards Air Force Base. At various points it is known as the Calf Canyon Highway, Carrisa Highway, Bakersfield-McKittrick Highway, Rosa Parks Highway, Rosedale Highway, Barstow-Bakersfield Highway, Bakersfield Tehachapi Highway, Kern County Korean War Veterans Memorial Highway, and Mojave-Barstow Highway.
State Route 99 (SR 99), commonly known as Highway 99 or, simply, as 99, is a north–south state highway in the U.S. state of California, stretching almost the entire length of the Central Valley. From its southern end at Interstate 5 (I-5) near Wheeler Ridge to its northern end at SR 36 near Red Bluff, SR 99 goes through the densely populated eastern parts of the valley. Cities served include Bakersfield, Delano, Tulare, Visalia, Kingsburg, Selma, Fresno, Madera, Merced, Turlock, Modesto, Manteca, Stockton, Sacramento, Yuba City, and Chico.
State Route 144 is a state highway in the U.S. state of California that runs through the Sycamore Canyon in Santa Barbara. It travels along Sycamore Canyon Road from its intersection with Alameda Padre Serra at the Five Points Roundabout to Stanwood Drive.
A diamond interchange is a common type of road junction, used where a controlled-access highway crosses a minor road.
State Route 39 is a state highway in the U.S. state of California that travels through Orange and Los Angeles counties. Its southern terminus is at Pacific Coast Highway, in Huntington Beach. SR 39's northern terminus is at Islip Saddle on Angeles Crest Highway in the Angeles National Forest, but its northernmost 4.5-mile (7.2 km) segment has been closed to the public since 1978 due to a massive mud and rockslide. It would cost a total of $100 million USD to repair the road.
State Route 71 (SR 71) is a 15-mile (24 km) state highway in the U.S. state of California. Serving Riverside, San Bernardino, and Los Angeles counties, it runs from SR 91 in Corona to the Kellogg Interchange with I-10 and SR 57 on the border of Pomona and San Dimas. The segment from SR 91 to SR 83 in Chino Hills is called the Corona Freeway, formerly the Corona Expressway and before then the Temescal Freeway. SR 71 is designated as the Chino Valley Freeway between SR 83 and the Kellogg Interchange.
A Texas U-turn, or Texas turnaround, boomerang, or loop around, is a lane allowing cars traveling on one side of a one-way frontage road to U-turn onto the opposite frontage road. Typically controlled by yield signs, these allow U-turning traffic to bypass two traffic signals and avoid crossing the local traffic twice.
State Route 47 is a state highway in the U.S. state of California, connecting Terminal Island to the mainland in the Los Angeles area. From its south end at I-110 in San Pedro, it heads east across the Vincent Thomas Bridge to the island and the end of state maintenance. The state highway begins again at the junction with I-710 on Terminal Island, crossing the Schuyler Heim Bridge north to the mainland and the second terminus, where SR 103 begins. Signage continues along a locally maintained route, mainly Alameda Street, to the Gardena Freeway in Compton, and an unconstructed alignment follows the same corridor to the Santa Monica Freeway (I-10) near downtown Los Angeles.
State Route 204 is a state highway in the U.S. state of California that connects SR 99 and SR 58 in the Bakersfield area. Passing through downtown Bakersfield, SR 204 also connects Bakersfield's three major freeways together. Only the northern 1.4 miles (2.3 km) has been built to freeway standards; the rest is a six-lane arterial road.
U.S. Route 101 (US 101) is a major north–south United States Numbered Highway, stretching from Los Angeles, California to Tumwater, Washington. The California portion of US 101 is one of the last remaining and longest U.S. Routes still active in the state, and the longest highway of any kind in California. US 101 was also one of the original national routes established in 1926. Significant portions of US 101 between the Los Angeles area and the San Francisco Bay Area follow El Camino Real, the commemorative route connecting the former Alta California's 21 missions.
Leif Ourston was a pioneer proponent of modern roundabouts in the United States, years before any had been built there. He opened his engineering company in 1984, at a time when the American engineering community considered any roundabout a radical and innovative idea, and even the most modest proposals encountered powerful opposition.
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