Decoding the past - U.S. 30 flyover bridge's secret messages

Aerial NW 2When you’re driving around Iowa, do you ever wonder why certain bridges or pieces of the transportation system look different than others? Did you know that many times there is public art built into these structures that have meaning? A recent project connecting northbound Interstate 35 to U.S. 30 near Ames tells an interesting tale of the connection between a university, technology, and transportation.

As you may know, the world’s first electric digital computer was built at Iowa State University by John Vincent Atanasoff and Clifford Berry. This Atanasoff-Berry Computer (ABC) propelled the world into the digital age.

When a new flyover bridge connecting northbound I-35 to westbound U.S. 30 was proposed, the Iowa Department of Transportation’s bridge aesthetics expert, Kimball Olson, devised a plan to incorporate the invention of the ABC into the art of the structure.

Bridge memorial sign
One of Olson’s trademarks on Iowa DOT structures is the use of color. He said, “From the beginning for this bridge, I knew I wanted to incorporate durable color using integral brickwork instead of any sort of coating like paint or stain that would require more maintenance. My first thought was to consider each brick as a pixel on a screen, with the possibility of rendering some sort of image on the piers. When it was clear that there really wasn’t enough surface available for that, I went back to the drawing board and began to rethink the pixel metaphor more broadly in terms of computer-based imagery. I did some reminiscing about my early college days when we were still using punch cards to write and run simple computer programs. The idea immediately struck me that I might be able to code messages into the brick patterns.”

Punch card machine“At the Iowa DOT, computers figure very prominently in our work. It would be extremely difficult for us to design and analyze modern bridges without them. We even have an old IBM punch card machine on display in one of the lobbies at the DOT. So, with ISU, the birthplace of the digital computer, and the bridge right here in Ames, the computer punch card analogy was the perfect fit for the bridge,” said Olson. “In addition, the Northbound rest area near Elkhart, just down the road is ABC themed. Having the bridge nearby helps enhance the story told at the rest area.”

In the early days, punch cards were used to code computer programs. A person would very carefully punch specific areas of one card, then the next and the next, just like lines of computer code today, but in a paper format. These cards would be processed through a machine that ‘read’ the code and performed the task the punches dictated. “Even one mistake meant that your program didn’t run or gave you erroneous results. And if you accidentally dropped all your cards on the floor, good luck trying to get them back in the right order!” Olson said.

As part of the normal procedure for projects like this, there were several public meetings about various aspects of the bridge. Olson said, “We developed a poster to show at these meetings that explained the idea behind the brickwork. That idea was very well received, so we continued our work.”

While the idea of the coded messaged in the bridge piers was developing, Olson did a lot of research on exactly how the cards were laid out and the FORTRAN computing language that was used in those old computers. In addition, Olson worked with other designers to develop the modern shape for the bridge piers and other elements that not only was functional but also allowed for the brick to be placed on the face of each pier. “I wanted a modern-looking shape, one that would appear to be of this time - the computer age - while simultaneously throwing the clock back 80 years to the time of Atanasoff’s invention,” he said.

Working with Carole Custer, director of ISU’s Office of University Marketing, the pair developed six coded messages that could be encrypted into the brick patterns of the bridge piers. Olson said, “Carole and I wanted to provide an opportunity for people to take a journey and learn the story behind the ABC.”

Pier 1 brick pattern
Olson said, “It was a challenge to create messages that perfectly filled all 80 columns of the punch card, such that the statements were accurate and didn’t seem contrived, and so the patterns looked complete in the finished work.” Continuing the computer theme, elements of binary code, one of Atansoff’s main principles for modern computing, were worked into other parts of the bridge like the abutment retaining walls. In addition, the two sides of each pier have the color scheme reversed, which further reinforces the binary code idea.

Pier 1 view A 10212019 lin1.2
 “Because we had planned to use brick all along for this bridge, there wasn’t significant additional cost to incorporate the pattern,” explained Olson. “I was out on the job site with the contractor and explained what we were doing. When I shared the messages with them, they took an interest in getting it right. Once they did the first few, they got really good at the patterns.”

Now that the project is complete and traffic is flowing over the bridge, it’s time to decipher the code. We invite you to visit to continue your journey into the history of the ABC and the messages embedded in the flyover bridge.


This sure was a great idea to honor these 2 inventors in a very lasting and unique way. They would be very pleased, I'm sure.

Glad you are still adding value and uniqueness to IDOT projects. No one better.

Dennis Smith

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