In 1903, a Vermont doctor named Horatio Nelson Jackson drove from San Francisco to New York in a Winton touring car and became the first person to traverse the United States in an automobile. At the time, there were no more than 150 miles of paved road in the country, mostly concentrated within cities. The path that Jackson traveled was alongrivers, mountain passes, flatlands, and the Union Pacific Railroad, and what roads he did encounter between cities were, in his description, “a compound of ruts, bumps, and ‘thank you m’ams’ [sic].” The trip took 63 days, 12 hours, and 30 minutes, but it inspired auto companies and other early car adopters to arrange trips of their own, sparking demand for long-distance highways.
The first automobile highways weren’t construction projects, and were referred to as “auto trails.” They were essentially suggested routes made up of existing thoroughfares, conceived of by private associations and codified with names such as Lincoln Highway, Victory Highway, National Old Trails Road, and so on. The associations marked the trails with signs or logos, and promoted the improvement of the routes, sometimes collecting dues from towns and businesses. Eventually, the U.S. government grew wary of the proceedings, and proposed the construction of a paved and nationalized numbered highway system. The proposal was adopted on November 11, 1926. The numbered highways were a marked improvement over the auto trails, but nearly 30 years after their adoption, Congress approved the Federal-Aid Highway Act of 1956, revolutionizing the highway system by building 41,000 miles of interstate roads. The interstates repurposed existing numbered highways, connecting and extending them for greater efficiency, and these roads are to this day our main mode of distance auto travel. Let’s look at when some of the country’s biggest and most vital interstates were built.
Interstate 70: Maryland to Utah
I-70 is arguably the oldest interstate in the U.S. When it comes to the interstate projects initiated by the Federal-Aid Highway Act of 1956, I-70 was the first both by date of initial construction (August 13, 1956 in St. Charles County, Missouri) and initial paving (September 26, 1956 just west of Topeka, Kansas). The highway runs through 10 states as it spans the center of the country west from Baltimore, connecting Pittsburgh, Columbus, Indianapolis, St. Louis, Kansas City, and Denver. I-70 also includes the highest car tunnel in the world, the Eisenhower-Johnson Memorial Tunnel near Denver, which has an average elevation of 11,112 feet. The most recentsegment of the tunnel is the 12.5-mile stretch through the narrow Glenwood Canyon, completed in 1992.
Interstate 80: New Jersey to San Francisco
Interstate 70 may be the first of the federal interstates to begin construction, but Interstate 80 likely has the oldest antecedents, as it approximates the route of Nebraska’s Mormon Trail (aka Great Platte River Road), dating back to the 1840s, and also parts of the Lincoln Highway auto trail from the late-1910s to mid-1920s. Its transcontinental span runs through 11 states. Construction of the modern-day I-80 began in Nebraska in 1957 and in Pennsylvania in 1958 (though the Delaware Water Gap Toll Bridge that later became part of I-80 was opened on December 16, 1953). A final 5-mile connecting segment was completed near Salt Lake City on August 17, 1986.
Interstate 90: Massachusetts to Washington State
Interstate 90 is another federal interstate that traces its origins to an older antecedent auto trail: the Yellowstone Trail from Plymouth, Massachusetts to Seattle, Washington that was founded in 1912. The first segment of newly constructed road for I-90 was opened in Spokane, Washington in November 1956. I-90 has the distinction of being the longest interstate, at 3,085 miles, and covers 13 states. The last link to its western terminus in Seattle was completed in 1993.
Interstate 40: North Carolina to California
Route 66 was perhaps the most famoushighway in the United States during the first half of the 20th century, inspiring a song and even a TV show. Interstate 40 is the longest of the five federal interstates that gradually replaced it, and it was I-40 bypassing Route 66’s final segment in 1984 that led to the iconic highway being decommissioned the following year. Construction of I-40 began in 1957 in North Carolina. Though the interstate stretches more than 2,500 miles between its eastern and western ends, its final segment was completed in 1990 in Wilmington, North Carolina — just 220 miles from its first segment’s completion in Kernersville, North Carolina.
Interstate 10: Florida to California
Interstate 10 is the transcontinental highway with the southernmost span, running through all eight states of the lower U.S. Similar to I-40, it served as a replacement for Route 66, primarily for the stretch between California to Arizona. Exact details about the first new construction stretch of I-10 are sparse, but it most likely took place in El Paso in 1960. The Papago Freeway Tunnel completed I-10’s final segment when it opened in August 1990.
Interstate 95: Maine to Florida
Interstate 95’s 1,920-mile span from Houlton, Maine to Miami, Florida makes it the longest north-south oriented interstate in the country. It crosses 15 states and Washington, D.C. (the most of any interstate), and it also established the first bus/carpool lanes in 1969. Since the route traverses more densely populated cities than any other interstate, its construction was often contentious, particularly in Philadelphia. The first new construction for I-95 began in the summer of 1956 in Richmond, Virginia, though the Connecticut Turnpike was the first stretch of I-95 that opened. The final stretch of I-95, a long unresolved gap on the Pennsylvania and New Jersey border, was finally completed in the summer of 2018. The event also marked a larger momentous occasion: the completion of the original federal interstate system first planned in 1956.