CONCRETE ROADS: The Heart of the Mother Road

Oct. 3, 2013

It is unlikely that any highway has ever or will ever again be immersed so deeply in the history, heritage and culture of our nation as Rte. 66. First dubbed “The Mother Road” in John Steinbeck’s classic, “Grapes of Wrath,” the highway was first commissioned in 1926.    


It is unlikely that any highway has ever or will ever again be immersed so deeply in the history, heritage and culture of our nation as Rte. 66. First dubbed “The Mother Road” in John Steinbeck’s classic, “Grapes of Wrath,” the highway was first commissioned in 1926.    

In the years that followed, the 2,400-mile highway, which connected Chicago and Los Angeles, was immortalized not only in literature, but also in television, music and many other facets of American culture. Beyond its iconic cultural standing, Rte. 66 also played an important role that impacted personal mobility, commerce, industry and tourism, and in some places, the roadway continues to do so today. 

Telling the complete story of Rte. 66 would be a daunting task, and because much of the history of Rte. 66 is captured in so many different resources, this article focuses on the Mother Road in Oklahoma, which has the distinction of the highest number of lane-miles still in service.

“Oklahoma has more than 400 miles of Rte. 66, which is more than any other state,” said Terri Angier, chief of media and public relations for the Oklahoma Department of Transportation (ODOT).

“Rte. 66 went completely through Oklahoma, connecting smaller towns, parks, museums, motels, restaurants, and other attractions,” said Gary Ray Howell, Transportation Specialist V and in-house historian, ODOT Planning and Research Division, adding that people in the cities and towns that dotted the route worked to create unique or novel places that would attract people. Many signs and symbols of these places—as well as sections of the roadway itself—have been preserved as enduring reminders of the Mother Road. “Route 66 is a highway museum,” Howell said.

Howell explained that before Rte. 66 became a reality, an important step occurred. The concept of a numbered highway system was approved during a committee meeting of the American Association of State Highway Officials (the forerunner to today’s AASHTO) in 1926. A month later, the Oklahoma State Highway Commission officially adopted the highway numbering system, according to the report, “Oklahoma Route 66: Roadbed Research Project (1926-1970):  A Survey of Roadbed and Integral Structures.”

One of those routes, U.S. 66, crossed Oklahoma border to border, according to the report, which said in 1926 only a relative few miles of the state’s highways were paved. After the designation of U.S. 66 in Oklahoma that year, “fledgling booster groups and other organizations soon came to the forefront in efforts to promote the highway,” the report said.  

How it started

ODOT has some exceptional records, which provide a view of the construction of Rte. 66. “From 1915 to 1923, additional state revenue and an increase in personnel allowed the department to develop into an organization of centralized authority for road construction,” according to information on a special section of the ODOT website. 

ODOT’s website also shows the construction of the first section of what would become Rte. 66 in Oklahoma began in 1919, with a water-bound macadam surface, macadam base and “Topeka asphalt” surface placed near the state capitol. The first concrete pavement (with exposed concrete surface) was a 7.825 lane-mile section placed in 1922 from Tulsa to Catoosa. 

“The passage of the 1916 Federal Aid Road Act allowed for the building of roads and bridges with matching Federal monies,” the website said. “In Oklahoma, the first Federal-aid project (FAP 1) was the construction of the Newcastle Bridge across the Canadian River in Cleveland County. Located on the Ozark Trails, it was completed April 23, 1923. The Oklahoma House Joint Resolution 16 passed March 16, 1917, to provide matching funding to accept this federal-aid funding. However, World War 1 interfered with the funding." He also noted even though this was FAP1, it was not the first FAP to be completed.

Counties and local city governments were responsible for maintenance of the local highway system, the website stated, adding that, “Farmers all along this network of trails and highways donated labor and equipment to keep the roads in shape. Signing of the various routes was accomplished by Good Roads associations and commercial auto trail booster groups.” 

The roadway was officially designated in Oklahoma on Dec. 7, 1926, and signage was erected across the state in April 1927, according to the ODOT website. In a letter to the Bureau of Public Roads (now Federal Highway Administration), Oklahoma State Highway Commissioner Cyrus Avery wrote that Rte. 66 would be a highway “that the U.S. Government will be proud of.” Avery also had served as a former county commissioner and staunch supporter of the Good Roads movement, as well as vice president of the Ozark Trails Association and president of the Albert Pike Highway Association. He is considered by many to be the “father of Rte. 66.”

From 1919 to 1940, almost 300 bridge and roadway construction projects in Oklahoma were associated with the construction of Rte. 66. The national Rte. 66 designation continued until April 1, 1985, when the designation was removed statewide.  

“Most of the original Rte. 66 concrete-paved sections still in use today are off the State Highway System. These sections are either as county roads or city streets,” Howell said, citing examples such as a section that can be found in a residential neighborhood called River Hill. The section of concrete was placed in 1927 and is still in service today.

“Many sections of county roads between El Reno and Clinton have original concrete pavement,” he said, adding, “Some sections of original concrete sections on the State Highway System now are found east of Erick and east of El Reno.” Howell noted that while some of remaining concrete sections were paved in 1926, most were built in the 1930s.

A strong equal                 
The standards for the road construction can be seen in the “Report of the State Highway Commission for the years of 1929 to 1930, Inclusive,” (dated Dec. 31, 1930). The publication described the “Bates Road Test in Illinois,” which first established the thickened edge pavement as the best design. Early in the 1930 construction season, the thickness of the concrete pavement was increased 1 in., providing a 7-in. thickness at center and a 10-in. edge. During the same time frame, reinforcing steel was increased from 5.74 lb/ft to 8.3 lb/ft.    

According to the report, AASHO declared the pavement design, “one of the most substantial now in use in the United States, and the equal of anything in use except adjacent to the great industrial cities.” The report goes on to describe the Oklahoma State Highway Commission’s adoption of 36-ft embankments, allowing for a 20-ft pavement and 8 ft shoulder on each side.

There are three things that seem to have contributed to the roadway’s longevity, Howell said. These included the use of more concrete to create a thickened edge; the use of “lip curbs,” especially on hills, which served to direct water onto a spillway to prevent damage; and the inclusion of steel to reinforce the concrete.

Strength-testing results in the 1930 Oklahoma State Highway Commission report showed the results of core samples dating to 1926. For 1925 and 1926, the average strength was 3,532 lb/sq in., and the strength of the concrete increased significantly through 1930, when the average strength was reported to be 5,367 lb/sq in.

The Oklahoma Route 66 Association 2001-2002 report notes that paving to a uniform standard across the state took approximately 10 years, adding that the paving standard changed from 18 ft wide in 1925 to 20 ft in 1930. The final section of Rte. 66 in the state was completed between Miami and Afton, an event that coincided with the opening of Miami’s Neosho River Bridge in September 1937.

In the interim, Rte. 66 was “paved piecemeal as matching federal funds became available.” According to the report, Rte. 66 meant a proliferation of new bridges and significant improvements to “sharp turns, zigzagging section line roads, at-grade railroad crossings, steep hills, flood-prone dips, and other impediments to convenience and safety.”

The report said Rte. 66 was comprised of sections that included existing brick, 2-in. asphalt over 5-in. concrete base, asphalt, and the most prominent of all, portland cement concrete. Most of the surviving first-generation pavement can be found in western Oklahoma, along with beveled curbs and drainage gutters. In western Oklahoma, much of the surviving concrete sections serve as a frontage road to I-40.

The report added that realignments continued long after the original paving was completed in 1937, most in response to “traffic demands, safety considerations, and a myriad of other factors to which evolving road-building technology could be applied.”

Although the authorization of the Interstate Highway System in 1956 may have signaled the beginning of the end for many sections of Rte. 66, the Oklahoma Route 66 Association report described how increased traffic in the early 1950s may have been an even earlier indicator. “In 1953, the first major bypass of a section of Route 66 occurred in Oklahoma when the Turner Turnpike opened between Tulsa and Oklahoma City,” the report said, adding that many sections were brought up to interstate standards, while others were removed, or eventually “reverted back to county ownership . . . or deeded back to landowners if not needed to ferry traffic.”

Journey to the Smithsonian

Although the number of sections of Rte. 66 in service may have diminished, the historic significance did not.

In the late 1990s, an assessment of a section of the concrete pavement placed at the end of 1931 to the beginning of 1932 led to the conclusion that they were not safe for current driving conditions. The section extended from the spur between I-40 and U.S. Rte. 281, midway between El Reno and Clinton in Canadian County.

Although the concrete remained strong, a portion of the roadway was rated in “critical condition because narrow lanes, poor sight distance and lake of shoulders made it unsafe for modern travel,” according to a December 2000 information release from the ODOT.

In 2000, the Smithsonian’s National Museum of American History contacted ODOT to determine the feasibility of donating a piece of Rte. 66 for its fall 2003 exhibition, “America On the Move.”  

Within months, ODOT and Plains Bridge Construction worked together to remove several sections of the original concrete pavement . The section of roadway was cut into eight, 50-ft  x 50-ft sections, each weighing about 9,300 lb, and then transported by semi-trailer trucks and flatbed trailers, Howell said. 

In 1999, the American Concrete Pavement Association presented a Lifetime Pavement Award to Rte. 66 in Oklahoma. Citing the award, Neal McCaleb, then U.S. Secretary of Transportation, said the section was “clearly built to last.”

“This slab has borne the wheels of commerce for over 65 years, and is still functional, as are the 400 miles of Rte. 66 that remain a part of the fabric of our state highway system today,” he added.

The section of historic road is part of a 20,000-sq-ft permanent exhibition about transportation and its significance to the nation’s lifestyles and economy since the 1870s. Angier explained that in addition to the roadway, many of the Rte. 66 signs and other historic items also came from Oklahoma. Among these items are paving bricks and a U.S. 66 route marker.  

“The main reason this section was selected was because of an increase in traffic in the area, which necessitated construction of new alignment, a four-lane divided highway,” Howell explained.  

The 5-mile safety improvement project on the U.S. 281 spur included the removal of 2 miles of Rte. 66, Angier said, adding that this left 3 miles of the original roadway, which was turned over to local agencies.   

Angier explained there initially was controversy about removing the roadway among Rte. 66 advocates, but the decision to leave the 3 miles of Rte. 66 proved to be a popular decision. Today, Canadian County still maintains this historic and still very functional section of roadway, Angier said, adding that what “began as a difficult situation turned into a great success.”

“Rte. 66 is absolutely priceless to the state of Oklahoma. It’s wonderful to see the original section being preserved,” Angier said, adding, “I cannot think of a more prestigious museum to display the section.”

Today, the section of Rte. 66 from Oklahoma, along with many Rte. 66 artifacts, is part of the permanent exhibit at the museum’s Kenneth E. Behring Center.

Although some of the original 2,400-mile structure and even more of the surface of the original Rte. 66 may be gone, the remaining patchwork of roadways stands as an indelible part of the nation’s history. With its record of most sections of Rte. 66, along with its contribution to preserving the history of the roadway, Oklahoma has earned its place as the heart of the Mother Road.