California Department of Transportation

California Celebrates 50 Years of the Interstate Highway System

The Interstate Highway System Turns 50

The Federal-Aid Highway Act of 1956 that brought America its unparalleled Interstate Highway System celebrates its 50th anniversary this year (2006). The Interstate Highway System has helped to transform our nation and our economy with more than 46,500 miles of interconnected highways. Indeed, the Interstate Highway System is prominent in the daily lives of most Americans. The distribution of virtually all goods and services and much of the nation's business and pleasure travel involve Interstate Highways at some point.

The American Association of State Highway and Transportation Officials (AASHTO), which represents the state departments of transportation in the 50 states, the District of Columbia, and Puerto Rico, wants to "Celebrate the Interstate!" both nationally and in individual states. At the same time, it proposes to address some of the policy questions the nation faces as we look forward to the next 50 years in U.S. transportation.

California is itself commemorating the 50th anniversary of the Interstate Highway System on June 16, 2006, at San Francisco's Lincoln Park, which was the western terminus of one of America's best-known historic roads, the Lincoln Highway.

The Origins of the Interstate Highway System

old car driving through mud
Early Road Conditions. Often, road conditions were abysmal, as this early traveler experienced while navigating through mud.

Good roads, or any paved roads at all, were not common as America entered the twentieth century, and they often failed to connect to other roads, especially between states. Likewise, road systems did not employ consistent signage, and motorists often got lost in trying to travel from town to town. As a young soldier, Dwight D. Eisenhower experienced the difficulties firsthand when traversing the nation in 1919. Following the route of the Lincoln Highway (later US 40), he and his crew took 62 days to cross the country and often broke down or met with delays caused by the bad conditions of the roads. This experience largely influenced his understanding of, and desire for, a workable national highway system. In 1956, President Dwight D. Eisenhower authorized the Federal-Aid Highway Act, also known as the National Interstate and Defense Highways Act.

Old car on route 8, Imperial County
Route 8, Imperial County, 1910. This image is another view of the road conditions early travelers endured.

Planning for a system of new highways actually began in the late 1930s, and in 1944 the National Highway Committee, appointed by President Franklin D. Roosevelt, developed plans for a national system of expressways, approved by Congress as the 40,000 mile National System of Interstate Highways. Funding did not come until 1952, however, when President Harry S. Truman signed the Federal-Aid Highway Act, which offered a down payment of $25 million for the interstates. Sufficient funding to build the nation's Interstate Highway System finally came under President Eisenhower, who led the campaign.

Currently more than 46,800 miles make up the Interstate Highway System (officially known as the Dwight D. Eisenhower National System of Interstate and Defense Highways), which features more than 14,700 interchanges, 55,500 bridges, and 82 tunnels. In elevation, it peaks at 11,158 feet at the Eisenhower Memorial Tunnel in the Rocky Mountains of Colorado and dives 52 feet below sea level along Interstate 8 in El Centro, near the Mexican border.

Distinctive Aspects of California and the Interstate Highway System

California holds part of three of the four longest interstate routes in the country. I-80 (Interstate 80) begins in San Francisco and stretches 2,899.54 miles to Teaneck, New Jersey, ranking second among the nation's longest interstate routes, behind I-90. I-40 begins in Barstow, California, stretches 2,555.40 miles to Wilmington, North Carolina, and ranks third. The fourth longest, I-10, begins in Los Angeles and stretches 2,460.34 miles to Jacksonville, Florida. In addition, California ranks second behind Texas in the number of interstate miles, with 2,455.74 miles, and second behind New York in the number of interstate routes, with 25 different routes. While I-90 and I-95 traverse the most states, at 16 and 13 respectively, I-80 travels through the third greatest number of states, including California. Likewise, I-10 ranks fifth as it traverses eight states, including California.

Highways for National Defense Ad
Highways for National Defense Advertisement, 1940. This advertisement appeared in a 1940 edition of California Highways and Public Works.
I-80 over Donner Summit
I-80, over the Donner Summit, September 24, 1964. Traversing over the difficult terrain of the Donner Summit.
I-40 construction
I-40, construction progress, west of Needles, April 5, 1971.
beaumont freeway
Beaumont Freeway, I-10, Riverside County, January 1, 1961

The History of Interstate Highways in California

The list of California's first sections of interstate is quite impressive. California already had more than half a dozen routes by 1947, totaling 1,938 miles, including I-5, I-8, I-10, I-15, US 40, I-80, I-505, and I-580. "Beltline and circumreferential" routes (more commonly called bypasses, such as today's I-710, I-280, and I-880) were added in 1955 bringing California's total interstate miles to 2,135. On June 24, 1957, I-80 became the first California freeway opened under the Federal Highway Act of 1956. I-10, one of the oldest interstates, was the first California interstate project to go to construction with interstate construction funds under the 1956 Act.

construction of I-80, Alameda County
Construction of I-80, Alameda County, August 15, 1948. Construction of I-80, which began in 1947, connects San Francisco throught Sacramento over the Sierra and was the first California freeway opened under the Federal Highway Act.

The number of limited access highways already in existence in California before 1956, when the Federal-Aid Highway Act was signed, underscores California's historic role as a leader and innovator in the construction of highway routes. Over 60 years earlier, on March 26, 1895, the state of California secured the title and right of way to the Lake Tahoe Wagon Road, which crossed the high Sierra into Nevada, and established a commissioner for this road. The Lake Tahoe Wagon Road, California's first state highway, which officially became Highway 50 in 1927, is also known as the "backbone of America" and is commemorated as such by the Highway 50 Association. Another early road, CA-1, first opened to traffic in 1912. It runs more than 548 miles along the Pacific Coast from just south of San Juan Capistrano in Southern California, north through the San Francisco Bay Area, to Leggett in Mendocino County. Running along some of the most beautiful coastline in the world, CA-1 has been designated an All-American Road by the Federal Highway Administration.

highway construction equipment
Construction of US 50 between Folsom and Placerville, March 1940. US 50, which is also known as the "Backbone of America," stretches more than 3,000 miles from Sacramento over the high Sierra to Ocean City, Maryland and crosses through Lake Tahoe, Central Colorado, Carson City, Kansas City, St. Louis, Cincinnati, and Washington, D.C.

Nationwide highway systems did not originate with the Interstate Highway System, but predated it. The Lincoln Highway, first envisioned in 1913, was one of America's most famous highways, affectionately known as "The Main Street Across America." The highway, arguably the first transcontinental highway in the United States, crossed through 14 states and spanned more than 3,300 miles, coast-to-coast, from Times Square in New York City to Lincoln Park in San Francisco.
Another famous highway, Route 66, was one of the original federal routes, established on November 11, 1926. It ran 2,347 miles from Chicago through Missouri, Kansas, Oklahoma, Texas, New Mexico, and Arizona before ending at the beach in Santa Monica, California. Route 66, a major migratory road west, especially during the Great Depression, currently exists as Historic Route 66, a National Scenic Byway, and is commemorated, by various organizations along the way, including the California Historic Route 66 Association.

US 40 in Citrus Heights
US 40, Citrus Heights, Sacramento County, April 4, 1951. Parts of the Lincoln Highway often passed through small communities, such as this, throughout the nation as it stretched out across 13 states from San Francisco to New York City.
construction of redwood highway, us 101 north of San Francisco
Construction of the Redwood Highway, US 101, north of San Francisco.

US Route 101, established in 1926, stretches 1,540 miles north from Los Angeles to Olympia, Washington. From Southern California to the San Francisco Bay Area, it follows much of the route of El Camino Real, the "royal road" of California's Spanish- and Mexican-era missions, while north of San Francisco it becomes the famed Redwood Highway.

I-580
I-580, May 19, 1937. I-580 is shown here between Dublin and Castro Valley after road widening construction.

Other California highways built before the Federal Highway Act of 1956 include the 1940 Arroyo Seco Parkway between Pasadena and Los Angeles, and I-80, built in 1947, which connects San Francisco through Sacramento over the Sierra to Nevada. In addition, portions of I-105, the Santa Ana Freeway; I-205, the Tracy-Altamont expressway; and the Livermore Bypass and Altamont Bypass, I-580, all predated 1956.

The Interstate Highway System in California

Of the 1,000-mile increase in highway miles authorized nationally in the 1956 Federal-Aid Highway Act, none went to California. The state, however, did receive aid for 1,938 miles under the original designation of routes in 1947, as authorized under the 1944 Federal-Aid Highway Act, and for several additional "belt-line and circumreferential" routes in the San Francisco and Los Angeles areas. All together, this brought California's total allocation up to 2,135 miles at the time of the 1956 Act.

Construction of the Arroyo Seco Parkway
Construction of the Arroyo Seco Parkway, September 1938. Construction of the parkway, seen here off Avenue 43 Bridge, began in 1938 and completed by 1940.

Exactly which segments of California's highways first utilized Interstate Highway System funding is hard to determine because California had already developed limited access highways to full freeway standards as far back as 1939, following the passing of the State's Freeway Law. For example, the Aliso Street Viaduct (later part of 1-5) opened in 1948, and the Arroyo Seco Parkway (Route 110), the first freeway in California, opened in 1940, although it is not officially part of the Interstate Highway System.

Traffic on the Harbor Freeway
Traffic on the Harbor Freeway, I-110, July 24, 1958.

Other pre-1956 routes included the I-105 (Santa Ana Freeway), I-205 (North Tracy Bypass), and I-110 (Harbor Freeway).

Timeline of Notable Events of the Interstate Highway System in California

1895
Bureau of Highways: R. C. Irvine, Marsden Manson, and L. Maude surveyed and visited every county in California. Their recommended highway system became the foundation of the system that exists today.

Lake Tahoe Wagon Road (US 50): First State Highway.

1909, 1915, 1918
Bond Acts: These Bond Acts outlined and provided the initial funding for construction of a connected state highway system.

1912
TransLab: The recently appointed California Highway Commission authorized the construction of a materials testing facility, forerunner of what became known as the Transportation Laboratory.

Test Lab
Test Lab, circa 1910s/1920s. An early employee is seen here working at the Test Lab to help improve California's roads and highways.

1915
Passage of "Convict Labor Law": The Department of Engineering was authorized to use convict labor for highway construction. Subsequently roads, particularly in remote areas, were constructed by convict labor for many years to come.

1916
Federal Bankhead Act: California received more than $150,000 in Federal Aid funds for the fiscal year ending June 30, 1917.

1918
Early State Highway Construction: By this date, several important highway projects were completed on portions of what would later become the U.S. Interstate Highway Systems. These include the Ridge Route (later part of US 99 and I-5) and the Yolo Causeway (later US 40 and I-80), which provided an all-weather link from Sacramento to San Francisco. Many other significant early state highways were also under construction or had been completed.

Ridge Route, I-5
Ridge Route, I-5, October 16, 1941. Ridge Route, shown here from Lebec to Bakersfield, winds over the San Gabriel and Tehachapi Mountains between Castaic Junction on the south and extends to the bottom of Grapeview Grade on the north where I-5 enters the great San Joaquin Valley.

1925
United States Highway System: Prior to the Interstate Highway System, the United States Highway System provided the first nationwide system of standardized routes. The Federal Aid Highway Act of 1925 created this system as a response to the confusion created by the more than 250 named highways, such as the Lincoln Highway and the Lake Tahoe Wagon Road, which were identified by names and colored bands on telephone poles. Instead, the new system used uniform numbers and a universally recognizable standardized shield for interstate highways. The most important change created by the act included the provision that state governments, rather than for-profit private road clubs, administer the system.

US 101 sign

1933
Breed Act: The Breed Act added approximately 5,900 miles of secondary highways and some 900 miles of urban city streets to the State Highway System. This transfer nearly doubled the mileage of the State Highway System. It was also the first of a series of events that began shifting the State Highway System's focus from rural to urban areas.

1947
Collier-Burns Act: In 1944, the California Highway Commission recommended a major post-war construction program. Senator Randolph Collier, known as "the Father of the Freeways," successfully directed this bill, which consolidated county road administration, required that the state maintain highways in cities, increased gasoline and diesel fuel taxes from 3 to 4.5 cents per gallon, increased automobile registration fees and weight taxes on trucks, created funds for all highways and excess motor taxes, revised apportionment of revenues from fuel taxes, and divided state highway construction funds between southern and northern California, with 55% and 45% to respectively.

I-80 over Donner Summit
I-80 over Donner Summit, June 3, 1966. The American Society of Civil Engineers awarded a "Civil Engineering Achievement of Merit" for the completion of I-80 over the Donner Summit in 1966.

1960, 1964
Conquering the Sierra: Beginning in 1960, nearly 50 miles of four-lane freeway were constructed in just 18 months, including the conversion of old US-40 into I-80, to provide motorists with an easier route to the 1964 Winter Olympics in Squaw Valley. Four years later, an additional 10 miles of I-80 were constructed over Donner Summit and through the Truckee River Canyon, judged by the American Society of Civil Engineers as one of the two best engineering feats of 1964 (along with NASA's Cape Kennedy) and awarded a "Civil Engineering Achievement of Merit" in 1966.

Highway 89 at Squaw Valley
Snow Conditions on Highway 89 and Squaw Valley, January 14, 1960. This image shows another route travelers could take to attend Olympic games.

1969-70
Passage of NEPA: The National Environmental Policy Act (NEPA), passed in 1969 and signed into law by President Richard M. Nixon in 1970, applies to federal agencies and the programs they fund. It requires that federal agencies, including the Federal Highway Administration, to consider environmental impacts before taking any significant action.

1970
Passage of CEQA: The California Environmental Quality Act (CEQA) is a California law enacted shortly after NEPA that requires government agencies to inform the public of the environmental consequences of government actions and to avoid or mitigate significant environmental impacts.

Caltrans logo1972-73
Creation of Caltrans: Previously the Division of Highways within the Department of Public Works, Caltrans became a separate department in 1973. The new name, Caltrans, short for the California Department of Transportation, symbolized the new broader view of transportation beyond highways alone.

1979
Last Link of I-5: On October 12, 1979, the new I-5, which runs from Canada to Mexico, was dedicated near Stockton.

I-5 Opening Ceremony
Opening Ceremony, last link of I-5, Stockton, October 12, 1979. Representatives form Canada and Mexico attended as well.

1987
State Sales Tax for Transportation: California Governor George Deukmejian signed a bill that allowed counties to ask voters for up to a penny hike in the state sales tax to pay for new roads and mass transit.

1990
Propositions 108, 111 and 116: Propositions 108, 111, and 116 were passed, designed to generate $18.5 billion for transportation improvements.

Highway 89 at Squaw Valley
I-105, August 26, 1987. Construction from LAX to Norwalk.

1993
Completion of I-105: The 17.3-mile Glenn Anderson (Century) Freeway, I-105, between Norwalk and El Segundo in Los Angeles County opened to traffic in 1993. The $2.3 billion project, which included interchanges to four other freeways, was billed as the last new freeway in Los Angeles.

Some California Engineering and Environmental Innovations

1916
Yolo Causeway: Work was completed on the Yolo Causeway, for the first time allowing year-round travel between the State Capital and San Francisco despite the area's regular floods. This causeway, which became part of I-80, was California's first highway project financed by the sale of highway bonds.

1953
Four-Level Interchange: The Hollywood, Santa Ana, Pasadena, and Harbor freeways were joined by the first four-level direct connector interchange, sometimes referred to as "The Stack."

The Stack
The Stack, 1954 .

1958
Carquinez Bridge (1-80): The "Big Cut" on the bridge's southerly approach was the world's largest at the time, involving 8,800,000 cubic yards of excavation in a cut that was 2,500 feet long, 1,370 feet wide, and, at its deepest point, 300 feet deep.

The Stack
I-80, Carquinez Bridge. Note the expanse of the southern approach.

1963
Westside Freeway (1-5): The 321-miles-long Westside Freeway was the longest freeway project undertaken by the State at that time on entirely new alignment. In addition, due to coordination with the California Aqueduct Project, the project required a close collaboration and development of new engineering technologies with Department of Water Resources and the Federal Bureau of Reclamation.

Westside Freeway, I-5
Westside Freeway, I-5, May 10, 1971, near the Stockton Channel.

1965
1-10 in San Bernardino and Riverside counties: Between Cabazon and Palm Springs, highway builders used newly developed machinery to put down four lanes of concrete in a single operation, a wider path than had been done before.

10-Ton Best Pulling 12-Foot Blade
10-Ton Best Pulling 12-Foot Blade, 1926. Construction of I-8 in Imperial County.

"Traveling deflectometer": This new device for measuring deflection led to new pavement overlay design procedure.

Construction of I-10 in San Bernardino County
Construction of I-10 in San Bernardino County, 1933. More modern technology led to the replacement of other construction methods, such as the equipment seen here.

1970
Last section of new Ridge Route (1-5): This eight-lane-wide, 43.2-mile-long section of Ridge Route, which traverses the rugged Grapevine and connects the San Joaquin Valley to the Los Angeles Basin, was constructed primarily on new alignment. A unique solution to the problem presented by the terrain was the use of separate alignments for each direction of travel, including the northbound lanes crossing over the southbound lanes.

1971
Sylmar Earthquake: On February 9, 1971, an earthquake rocked the northern San Fernando Valley, near Sylmar, measuring a magnitude of 6.6 on the Richter scale. The Sylmar Earthquake revealed that many common bridge design details were inadequate for a force of this magnitude. The subsequent research and findings triggered a statewide seismic retrofit program, and the significant changes immediately made to California bridge design standards also became the basis for a new national code.

Pine Valley Bridge Construction
Pine Valley Bridge Construction, March 19, 1974.

1975
Pine Valley Bridge (I-8, San Diego County): The Pine Valley Bridge was the second and the largest bridge designed for construction utilizing a segmental balanced cantilever method. The bridge carries I-8 over 200 feet high above the floor of the valley.

1984
New Dumbarton Bridge: Opened to motorists in December of 1984, the New Dumbarton Bridge connected San Mateo and Alameda Counties and spanned 8,600 feet across the narrowest neck of San Francisco Bay. Approach embankments were constructed with a number of innovative techniques, including paper wick drains and geomembrane reinforcement. In addition, because of the bridge's location within the San Francisco Bay National Wildlife Refuge, special care had to be taken during construction to avoid environmental disturbance.

Pine Valley Bridge Construction
New Dumbarton Bridge, 1986. Note the fishing pier.

1990
Automated Pavement Marker Truck: Developed jointly by University of California, Davis and Caltrans, the Automated Pavement Marker Truck allowed for the installation of raised traffic markers ("Bott's Dots") more rapidly, effectively, and safely.

2000
Environmental - "Greening the Fleet": Caltrans continued to lead the way to cleaner air by using viable, emerging technologies, and by staying ahead of government regulations, in a program called "Greening the Fleet." This forward-looking initiative began in August of 2000 with a request from Director Jeff Morales to the Caltrans Division of Equipment to lower emissions from the Caltrans mobile fleet.

2003
"Bubble-Cushion": This new technology was designed to protect fish and other wildlife during construction on the Benicia-Martinez Bridge on I-680.

Future Plans

Caltrans continues to lead the way in innovation and seeks persistently to improve transportation. For example, Interstate 80 from San Francisco to the Nevada state line is currently undergoing major renovations and improvements. In the Sacramento area, Caltrans is planning to add 10 miles of carpool (HOV) and auxiliary lanes to I-80 in the median from the Sacramento River Bridge to the Capitol City Freeway split, and an additional five-mile segment of HOV and auxiliary lanes will be constructed from the Sacramento/Placer county line to east of Highway 65. Over the Sierra, the I-80 workhorse is getting a much-needed face-lift from Auburn to the Nevada state line.

Major rehabilitation projects, now underway in the Auburn and Gold Run area and scheduled in the next few years around Donner Summit, will replace existing asphalt with Rubberized Asphalt Concrete (RAC) in the lower elevations and Portland Cement Concrete (PCC) in the higher elevations, upgrade safety features, improve existing on and off-ramps, enhance lighting, and install additional Transportation Operation System elements.