Photo 1920: One of the 63 sections of the Bates Experimental Road
“The Transportation History Blog” by the American Association of State Highway and Transportation Officials (AASHTO) recently wrote an article about an influential 1920s Illinois road test. The Transportation History Blog is a collection of short articles about history and transportation where AASHTO publishes an item/article every weekday, and occasionally highlights other historical transportation items during special periods of the year.
Between 1920 and 1923, the Illinois Division of Highways (IDH)—now part of the Illinois Department of Transportation (IDOT)—oversaw a series of tests to help determine the best type of pavement to use on that state’s roads. IDH launched these tests at a time when it was preparing for major construction projects to accommodate increasingly heavy motor vehicle traffic throughout the Prairie State. In particular, state officials needed to determine how to pave highways to withstand the then-new phenomenon of heavy truck traffic.
1922: A report noted, “At the time, the State had in contemplation the expenditure of possibly one hundred million dollars for a road improvement program. To undertake a program of this size without definite scientific knowledge of the behavior of certain pavements under truck traffic and rural conditions … was deemed unwise.”
The tests specifically took place on a 2-mile (3.2-kilometer) stretch of road that had been built by IDH on state property near the community of Bates in central Illinois. The experiments conducted on that segment became collectively known as the “Bates Road Test”, as it ran from Bates (an unincorporated area west of Springfield) to Farmingdale Road.
This experimental road encompassed a total of:
—63 sections of pavement
—Each 18 feet (5.5 meters) W
—Between 100 to 250 feet (30.5 to 76.2 meters) L
—24 of these sections were built of concrete
—22 consisted of bricks
—17 were made of asphalt
The Bates Experimental Road of 1920-23 was, literally and figuratively, a groundbreaking study. Contractors’ and Engineers’ Monthly Magazine noted, “In each type of pavement, the sections varied from those so thin that they were sure to break under the lighter test loads, to sections which were considered strong enough to successfully support the heaviest load permitted by the state traffic laws.” During the tests, a fleet of U.S. Army trucks made thousands of round trips on the road. These vehicles carried loads of up to 10 tons (9.1 metric tons) for their runs.
Clifford Older, Chief Engineer-IDH, focused on how the test runs showed the need for increased strength at the edges of a road. Older explained “Rigid pavements having a uniform thickness or edges thinner than the center are greatly unbalanced in strength and will fail along the edges long before the wheel loads are reached which will cause the destruction of other portions of the slab.”
1923: In the August issue of Municipal and County Engineering Magazine, H.F. Clemmer, Engineer of Materials-IDH, highlighted the benefits of the Bates Road Test, and noted, “Three years of investigation on the Bates Experimental Road has provided an immense volume of data on the actions and characteristics of the soil making of the subgrade of that road.”
For the first time, the Bates Road Test gave road engineers data on:
—Soil mechanics
—How to select pavement types
—How to select pavement thicknesses
—How to select pavement construction methods to match an individual highway’s expected use
—A base for officials from which to set weight limits for both trucks and roads
… officials estimated that the
pavement tests saved the state
$9 million in construction costs.
Viewing the Bates Experimental Road, 1922 (Lincoln Highway
Digital Image Collection) Click to enlarge.
1926: The Associated Press reported that “this experimental road attracted international attention when information on hard road building was scarce.” The doubters were wrong!
The Bates Road Test was widely hailed as a big success. The results indicated that, in terms of durability, concrete was the best material for building highways at that time.
Over the next several decades, the legacy of this road test eventually extended well beyond the borders of Illinois. As one of the best-documented initiatives of its kind during that era, the Bates Road Test helped set the stage for larger-scale efforts that were also undertaken to assess the most optimal materials and designs for the development of long-lasting roads.
1930s: The U.S. Bureau of Public Roads conducted several loading tests on concrete pavement.
1950-51 Maryland: A research project was carried out to gauge the service life of highway pavements and the impact of wheel loads. This project, called “Road Test One-MD”, was administered by the Highway Research Board (the present-day Transportation Research Board-TRB) and financed by the District of Columbia and 11 states. The Maryland study used an existing road near the town of La Plata to test the impact of round-the-clock truck traffic on concrete pavements.
1953-54 Idaho: The Western Association of State Highway Officials (WASHO) sponsored a road test. The WASHO Road Test focused on the impact of heavy truck traffic on flexible (asphalt) pavements. This road test—likewise administered by the Highway Research Board—was financed by a total of 11 state highway departments.
Between 1958 and 1960 Illinois: An even more comprehensive experimental effort took place with the AASHO Road Test. This series of tests was sponsored by American Association of State Highway Officials (AASHO) and supervised by the Highway Research Board. The AASHO Road Test was carried out carried out along a seven-mile (11.3-kilometer) track of two-lane highway between the cities of Ottawa and LaSalle, an area that is approximately 125 miles (201.2 kilometers) north of where the Bates Road Test had occurred. (on November 13, 1973, AASHO was renamed the American Association of State Highway and Transportation Officials (AASHTO) (Wikipedia)).
1975: Lloyd Loving of New Berlin in Sangamon County, Illinois, was interviewed by the Oral History Project-Sangamon State University (now the University of Illinois Springfield), and recalled that when he worked on the road in 1922, many people thought the experiments were a waste of money:
“(N)o one realized at the time that in 50 years there’d be as many hard roads in the country as there is, and I think they thought that was a lot of money to spend testing. And, then turn around and wear it out driving trucks back and forth … that seemed to be the most foolish thing, wearing it out!”
In addition to Lloyd Loving, Thomas T. and Mary J. Wilson, George Marr, and Robert White for the University of Illinois Springfield oral history program discussed their parts in the Bates Experimental Road.
For the “Illinois Digital Archives” interviews/memoirs, please go to:
“Illinois Digital Archives” interviews/memoirs:
Lloyd Loving: http://www.idaillinois.org/digital/collection/uis/id/2977
Thomas T. and Mary J. Wilson, George Marr, and Robert White: https://cdm16614.contentdm.oclc.org/digital/collection/uis/search/searchterm/bates
For links to the above article, please go to:
Transportation History Blog article: https://transportationhistory.org/2020/10/28/an-influential-road-test-is-conducted-in-illinois/
Bates Road Test Sangamon County Archives: https://sangamoncountyhistory.org/wp/?p=2601
Sangamon Historical Society: https://sancohis.org
Bates Road Test Illinois Archives: www.idaillinois.org/digital/collection/isl/id/19235
Some original content from Sangamon County Historical Society: https://sancohis.org
“Illinois Digital Archives” interviews/memoirs:
Lloyd Loving: http://www.idaillinois.org/digital/collection/uis/id/2977
Thomas T. and Mary J. Wilson, George Marr, and Robert White: https://cdm16614.contentdm.oclc.org/digital/collection/uis/search/searchterm/bates