Skip to main content

Latest Generation I-35 Signs Have Long History Combining Function, Technology

Back to Volume 8, Number 2


It's the new sign of the times.

With the touch of a button, a message suddenly appears on the large, overhead and easily seen Dynamic Message Signs (DMSs) placed along the finished I-35 projects in the Waco District. Employees of TxDOT's Traffic Management Center in Waco can type a message on their computer screen, hit send, and the message instantaneously appears on I-35.

"Signage and technology have certainly come a long way since the early days of automobile travel, with some of the biggest advancements happening in the last 10 years," explains TxDOT's Chris Pruitt, Waco District traffic engineer. "When a message needs to be displayed right away, we have that ability at our fingertips."

Stop signs over time

Stop signs have evolved over time—based on research into effective display to optimize roadway safety—and then adopted by the Manual on Uniform Traffic Control Devices, first published in 1935. Images courtesy of Gene Hawkins, professor in Texas A&M University's Department of Civil Engineering and research engineer at the Texas A&M Transportation Institute.


Some of the more urgent messages on the new DMS signs would indicate freeway and lane closures, and they could be accompanied by flashing beacons that make sure you notice. But most often, the overhead DMS will display amber or silver alerts, travel times to destinations ahead, and even slogans from TxDOT public awareness campaigns.

Signs have certainly changed since horseless carriage owners in New York City decided that travel signs were needed to help with directions.

"The year was 1899 when the members of this horseless carriage group formed the first automobile club, with part of their effort directed at placing and maintaining roadway signs so folks wouldn't get lost," explains Gene Hawkins, a professor in Texas A&M University's Department of Civil Engineering and a research engineer with the Signs and Markings Program at the Texas A&M Transportation Institute.

Hawkins, a traffic control device history buff, has written extensively about the subject, including the evolution of the Manual on Uniform Traffic Control Devices (MUTCD), which standardizes traffic control devices across the nation. Hawkins developed a website that includes every edition of the MUTCD: MUTCD History.

His research turned up some interesting facts about sign history. For example, it was these individual automobile clubs across the country (and local police departments) that took on the responsibility of placing roadway signs. In those days, shapes and colors of signs were unique to a given area.

"The early automobiles could not drive very far or very fast, so there was no real need for standardization," Hawkins says. "It wasn't until 1922 that the first effort was made to establish uniformity between states. It was becoming clear that in addition to travel signs, we needed signs to control the flow of traffic."

Hawkins says the colors and shapes of signs evolved over time. For example, signs were originally very simple with black or white backgrounds. In 1961, green was used for guide signs, and in 1971, orange was added to the mix and used in work zones.

According to the MUTCD, "The use of red on signs is limited to stop, yield, and prohibition signs. A white background indicates a regulatory sign; yellow conveys a general warning message; green shows permitted traffic movements or directional guidance; fluorescent yellow/green indicates pedestrian crossings and school zones; orange is used for warning and guidance in roadway work zones; coral is used for incident management signs; blue indicates road user services, tourist information, and evacuation routes; and brown is for guidance to sites of public recreation or cultural interest."

So what's next when it comes to signs?

Pruitt thinks it won't be long before roadway signs are full color LED boards that can display videos. But Hawkins takes it one step further. "With the rise of navigation aids, you may see fewer and fewer signs. But in a couple of generations from now when our highway system is only driven by automated vehicles, signs may disappear altogether," he says.

Back to Volume 8, Number 2

My35 logo

Central Texas News

Contact

Jake Smith
I-35 Public Information Officer
254-867-2705
Contact My35

TxDOT Waco District
100 S. Loop Drive
Waco, TX 76704

©2022 Texas Department of Transportation • All Rights Reserved