Many important roadways that people travel today began as trails traversed by horse and wagon. As the United States grew and expanded westward, and as first bicycles and then automobiles took to the roads, many of those transportation routes transformed into significant highways, thanks to the design work and execution by the civil engineers on the job. Take a look at these 6 famous roads that were important roads in history — and explore how they were created.

1. The Lincoln Highway

Automobiles were still a novelty when the Lincoln Highway was proposed in 1913. Entrepreneur and auto enthusiast Carl Fisher wanted to create a coast-to-coast highway suitable for cars. Less than half the route used already-improved roadways. That meant that civil engineers had to design new sections, which specified a 40-foot wide roadway made of concrete laid 10 inches deep to handle the weight of the vehicles, along with curves banked to handle 35 mph traffic complete with guard rails. Sections of the roadway followed historical trails and roads, including the Lancaster Turnpike, the Conestoga Road, and the Mormon Trail, and much of the Lincoln Highway later became Interstate 30.

2. The Historic Columbia River Highway

This roadway that parallels the Columbia River through northern Oregon was the first U.S. highway to be designed specifically to take advantage of its scenic elements. While it served the practical purpose of connecting inland Oregon to the Pacific coast, its design ignored many practical considerations, with civil engineers adjusting the route (at greater expense) to take motorists to scenic vistas. The engineers also designed a special drainage system that incorporated gutters, a raised center, and culverts over heavy areas of flow. The Columbia River Highway, which required 27 bridges and five tunnels, was designated a National Historic Civil Engineering Landmark in 1984.

3. Route 66

Very few highways get their own songs, but Route 66, which was designed to connect Chicago to Los Angeles, was one of the most famous roads in U.S. history. Beginning in 1926, Route 66 became the primary road for those heading west, including people moving from the Dust Bowl in the 1930s. Beginning in 1938, civil engineers worked to upgrade sections from gravel road, turning Route 66 into the country’s first completely paved highway. Some of the road’s hairpin curves in Arizona’s Black Mountains were so dangerous that travelers often hired locals to drive them through the section. While the creation of Interstate 40 as part of the Interstate Highway System caused Route 66 to be decommissioned, portions of the road were later restored to scenic byway status, and some sections are on the National Register of Historic Places.

4. The Farm Highway

One of the oldest roads still in use in the United States is the Farm Highway, which was first built in 1696. While some of the original dirt road sections have been preserved as historic sites, the northern portion of the road was incorporated into the Huntington Turnpike in 1828. While the road became neglected by the 1930s, in the 1950s and ’60s, civil engineers got to work to extend the road. The Farm Highway holds many historic sites, including homes and fountains, along its 11-mile stretch.

5. Pacific Coast Highway

California’s State Route 1, commonly known as Pacific Coast Highway, runs from the southern part of the state almost 700 miles, passing through Los Angeles and San Francisco and traveling across the Golden Gate Bridge along the way. When combined with U.S. Route 101, the road takes motorists up and down the entire West Coast. The original section of PCH, as the famous road is often called, was built between Ventura and Santa Barbara, with wooden causeways to carry travelers over coastal flooding. The highway’s most difficult section to build connects Big Sur and Carmel to San Simeon, the site of Hearst Castle. It took civil engineers 18 years to build this 74-mile section of road, which also required the design and construction of 33 bridges. While this section of road is twisting and prone to landslides, it’s considered one of the most beautiful scenic drives in the country.

6. The King’s Highway

Begun in 1650, the King’s Highway, also known as the Boston Post Road, is the oldest road in the United States. As the primary north-south transportation route during America’s colonial times, it ran from Boston to Charleston, South Carolina. Most of the King’s Highway has been taken over by various U.S. highways, including U.S. Routes 1, 20, 206 and 13. Civil engineers began to convert the old road to a paved highway largely in the 1920s. Many of these routes have in turn been replaced for high-speed travel by Interstate 95.

At Keck & Wood, we respect the impressive civil engineering that went into the creation of America’s most famous roads. We’re here to deliver transportation projects ranging from designing and constructing major highways to providing traffic engineering solutions, all with an eye to effectiveness and safety.