Ottawa Test Loop

Its hard to pay attention to the brown "point of interest" signs on the highway nowadays. We're usually whizzing past them attempting to avoid the droves of distracted drivers playing with their GPS, reading a John le Carré novel, shaving with a USB-powered Norelco and drinking a Sobe life water while hunting for the hottest song on their iPhone 5 this week. Having recently spent some time up north with my family for Thanksgiving, Sarah and I once again passed the AASHO Test Road Site sign just outside of Ottawa, Illinois on Interstate 80. For years we have passed this marker and wondered what it stood for. It had to be a test road area for asphalt or cement we thought. We'd both take turns guessing what the AASHO acronym stood for. American Asphalt Society of Highway Officials? How about the Amalgamated Asphaltian Supporters for Huge Opportunities?

That game got old pretty quick.

A cursory internet search produced no information until very recently. Like this morning. After learning about the Ottawa test road's history and the important role Illinois played in the development of the pavement we drive (distracted) on every day, I thought it would be neat to share it here.

In reality the acronym stood for the American Association of State Highway Officials. The group got its start back in 1914 as a non-governmental organization that set standards for how roads and highways were designed & built. In the 1970's, the group incorporated the word "transportation" into their name since they also had a hand in various other forms of travel. As the U.S. was gearing up for the construction of a large interstate highway system, the AASHO wanted to ensure that engineers, government officials, and contractors had the information they needed to lay down a product that would hold up for decades. They also wanted to use that data to inform the government on how much money it would cost to maintain such a vast infrastructure so that they could adjust the gasoline tax rates accordingly. Then came the questions. What was the best type of concrete mix for heavy loads? What type of road bed created less rutting over time? What methods of patching cracks worked well?  These were just a few of the questions that the AASHO had, and the answer to those questions was the Ottawa Test Site.

The plan for the test road site was sketched out by the AASHO team and was bordered by US Route 6 to the south, and nestled between Illinois Route 178 in Utica and Illinois Route 23 near Ottawa. The configuration would call for six test loops over a seven mile stretch of virgin farmland. Different loops would be subject to various tests of actual vehicular traffic over a two-year period.

Construction of AASHO Test Track. Circa 1956.

Construction began in August of 1956 and the various loops were assorted in size, application, and building method. Some sections used an asphalt mix, while others were straight concrete.  There were a total of more than 800 short road test sections. Nearly 20 small bridge spans were crafted to examine everything from bracing techniques to pavement degradation. In all aspects, the AASHO engineers did their homework. 

The U.S. Army Transportation Corps carried out tests at the Ottawa Test Loop. Neighbors included miles of corn field and country roads. Photo Credit: Gerry Buehler

Ribbon Cutting Ceremony at Test Loop #6. October 15, 1958.
By October of 1958 the site was prepared and  the first traffic simulation occurred. Teams of Army drivers would circle the loops in heavy trucks and  trailers for hours on end to put the pavement through its paces. While the average Chevrolet weighed somewhere in the neighborhood of 3,500 pounds, a 1953 Mack Model B semi of the same era tipped the scales at 13,000 pounds...empty. You can see the value in running something more heavy duty if you're serious about testing its strength.

A truck leaves a turn-around and enters the straightaway at the Ottawa Test Loop.  Photo Credit: Gerry Buehler      

If you look at the map of the test site above, you'll  notice the army barracks on site. I'm sure working there had its high points, but to me, driving a 1950's semi truck in a circle all day in the middle of the Illinois countryside doesn't sound appealing. The value of their work was ultimately realized by the engineers and number crunchers in the main office. The data that was collected was indeed carried out during their 'experiments' behind the wheel. This laboratory was open until November of 1960, when the testing ceased and the AASHO compiled the data for publication and reference. 

Fuel Stop. Circa 1958
By 1962 the Ottawa test site had a new neighbor: Interstate 80. Life moved on and I'm sure by then there was a mountain of paperwork that was generated by years of study. All that's left of the site today is a short part of one of the loops and a brown point of interest sign on I-80 that most of us don't pay much attention to. In the end, what did this huge laboratory experiment yield?  It introduced the Generalized Forth Power Law, stating that a vehicle's damage to pavement was related to the 4th power of their axle weight. Or, in a nutshell, the tests gave engineers the proof they needed to make the following earth-shattering statement: 

Big trucks wreck roads quicker than small cars do.

And as more Americans wanted more and more goods and services delivered to them in the post-war boom years, the folks at the AASHO knew that more and more trucks would have to travel the interstates full of heavy trailers. Trailers crammed full of shiny Kelvinator refrigerators, Philco television sets and cases of Bubble Up cola. It wasn't just the big trucks that needed to go on a diet. The average weight of the American automobile was also creeping up toward 4500 pounds by the end of 1950's and there were more of them. More motorists and wider use of popular road network meant someone would have to eventually take care of it. This would eventually put a financial burden on the federal government to maintain the massive interstate system that was already under construction. Armed with the evidence, the AASHO clearly spelled out what causes the most damage to a highway and the best ways to counter that damage by sound construction and maintenance methods. Pretty neat stuff when you dive into the history of a simple road sign. If you pass it next time you're on I-80, give it a glance. That stretch of road near Ottawa, Illinois will never look the same to me again.

Epilogue, 5/2015 : I would like to extend a hearty thank-you to Gerry Buehler for sharing his service in the U.S. Army and for sharing his experience and photos from his time at the Ottawa Test Loop in 1960. (You can read his recollections in the comments section below.)

Its incredible history and we're grateful for your willingness to get in touch.


*Photos in today's post were also courtesy of the Federal Highway Administration. They're good people. 



  1. Thanks for your article. We moved to Ottawa in 1956 when my father got a job as an Administrator at the Road Test, and stayed until things closed down. As a boy, I visited the place a couple times and watched the trucks circling the loops on their endless routes, and hope the drivers enjoyed their view of the beautifully flat Illinois landscape.
    Best from

  2. Talovich,

    Thank you for sharing your comments and for stopping by. Your father was an Aministrator there? It must have been a strange sight for a little one back then. Nice chatting with you, and take care!


  3. A good friend of mine worked on the road test. We drove past the site around 1976 when I was 22 years old and he commented on how he had worked on the road test when he was in the army. He was a WW2 vet. He told me stories about what he did and how several guys were killed while working the road test. They must have crashed their trucks while on the test loops. He was very compelled to go into town & visit some of his old hangouts. It did not mean much to me at the time but I now go past the test site often and it makes me think of him. I eventually lost touch with him & he has since passed on. I should have payed more attention to his stories but you know how kids are.

  4. Thank you for shedding some more light on the test loop and adding some stories. Its a unique place and I'm glad you shared your friend's connection to it. Cheers!

  5. Hi, Daryl:
    My name is Gerry.
    Ran across your post and thought you might me interested in some info I can give you on the AASHO Test Site. I was stationed there from the end of February to the last few days of the Army's role at the end of November, 1960 The Army Transportation Corps in Virginia supplied the drivers from Fort Eustis and Fort Story. Almost everybody was a "short-timer", meaning they had 3 or 4 months left of service. After leaving the test site we were transferred to Fort Sheridan in Highland Park and separated from active duty. Most of the guys didn't have military driver's licenses but that didn't really matter because the Army gave us a quick course in truck driving. On the drawing above you see loop 1(f) and loop 2(e). 1 was laid out and never driven on. It was used to see just what the weather itself would do it. Remnants are still there and marked with a sign. Loop 2 was where we started driving stake and platform trucks loaded with concrete blocks. After a while we moved up to the tractor trailers loaded/overloaded with concrete blocks. There were two lanes with the trucks alternating left to right about 50 yards behind the truck ahead of you. I believe we were going about 40MPH. The rules were simple: no passing, no speeding, and stay awake. The loops ran six days a week. We would get Sunday and a weekday off. The guys that were killed were before my time there, but the story was that they had indeed fallen asleep and their loads shifted and killed them. The turns were slightly banked going in and leveled out going out. We had AM radios mounted to the roof of the cab but really couldn't get good reception and were lucky to pick-up a strong Chicago station. If a crack or hole developed in the pavement some minor repairs may have been done, but generally speaking we were to just drive over them and see how much punishment the road would take. After a while steel sheets were used to cover the breaks and we kept on driving. The trucks took a beating and I would guess that the manufactures learned a lot from these tests. The mechanics who kept these rigs running must have been magicians. I'm not saying the trucks were unsafe but they sure rattled a lot. I don't know if the mechanics were Army or civilians.
    Look at the drawing above and you will see frontage roads above and below the loops. When driving at night the only lights we saw were from the trucks and distant farm houses, then all of sudden you see headlights coming at you and it looks like your going to have a head-on crash. Well, when the vehicle on the frontage road came over the rise the headlights appeared out of nowhere. Took a little while to get used to it. Yes, it was boring and monotonous. I remember on guy who hallucinated and insisted he saw a giant bird swooping down on his truck. I drove for a couple of months and then got the company clerk job because I had so much time left and would be around to almost the end of the project. As I said, I shipped out to Ft. Sheridan about Nov 25 or 26 and the Army ended its role on the 30th. (I don't think they shut down because I left and couldn't get on without me, but that they had that date picked a long time prior. But then, who knows?)

  6. "Blessed Is He Who Drives Around In Circles, For He Shall Be Known As A Big Wheel"

    That was our motto at Wallace Barracks. We lived in steel buildings on concrete slabs. There were two companies of troops there. To say it was laid back would be an understatement. No gate, no fence, one MP, no KP, no marching, nothing military. Guys were coming in and shipping out almost every day. Don't know how many passed through there, but I would guess hundreds. We were 2nd Army in 5th Army territory so we were pretty much independent. Ft Sheridan would send a dentist or a doctor to check us out, but it was not a regular thing. We were so independent that while the rest of the Army was eating meals that some unknown nutritionist chose, we had a menu committee. We would get together once a month to plan the next month's meals. Since we had free reign we ate very well. The food order would be placed with a market in town and picked-up as needed. Not once did we put SOS on the menu. (If you're not familiar with that, ask a Vet)
    Once I got the company clerk job my life really improved. Now I could hitchhike home to Chicago on the week-ends. Normally I would have to work a half day on Saturday, but I had a great First Sargeant (actually Sargea
    nt Major). He lived south of Ottawa and we would cover for each other on alternate Saturdays so we would get a full two days off.
    I don't want to ramble on, so I will close. Looking back at the experience, it was, an experience. Had some funny times out there and don't recall any bad times.
    If you're interested, I have a couple of pictures I'll send you.
    Hope this helped your curiosity.


    1. Gerry, thank you so much for taking the time to write this and share your personal story about the Ottawa Test Loop! I am very grateful for your insight and story. I especially liked the fact that you helped paint a picture of what the daily routine there was like in the thick of it. (I chuckled at the SOS story, too!) Many don't know of this story and I'd love if you'd be willing to share any pictures you may have, would that be okay?

    2. Just wanted to let you know that your work on the AASHO road is not forgotten. I am the director of the Utica museum and we have a new display on transportation which includes photos of the trucks you guys used. I also wrote a book -Back to the 50's which has a lot more information on the Army's participation including the mishap on opening day when the brass was there.
      Ron Bluemer

    3. I'll be sure to stop in the museum and look you up next time I visit Utica, Ron. I have a couple pictures I'll bring along;


  7. My father was with the AASHO Road Test from 1955-1961. I went to grade school in Ottawa during those years. We lived on the east side. My father was chief of the data analysis group and there were mountains of data. I remember seeing the loops being constructed and we spoke often of the 24/7 truck driving. Toward the end of the project his group acquired a computer made by Bendix and was an advanced machine. I think I recall it had 1,800 bytes (!) of usable memory. I would go to the office with him sometimes on weekends and he would give me commands to input to the computer, via an IBM Selectric. Its operating system was on paper tape (its only i/o) and had to be fed in with each boot up. The were a several prominent scientists brought in from around the country for the project. Our family would reminisce often over the years about Ottawa and the Road Test. A couple weeks ago I was driving across country on I-80 and was surprised to see a AASHO commemorative sign on the highway and right behind it was I think was the old office building, originally built amidst endless acres of corn. For Yugan's post above, I think I remember your father's first name as Pete?

    1. Thank you for sharing your memories about the test loop and growing up in Ottawa. I'll bet it was comforting to see the AASHO sign there when you passed by.


  8. I was stationed there from May 1960 to Feb 1961 . Was on loop 5 drove 39000 miles there. We lost 1 driver when I was there. Had lot of good mmemories of being there. Would like to have some pictures from there.Or hear from anyone who was there when I was. Wm Kaltenbach 149 Roberts Jerseyville,Il 62052 or


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