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Patrolman's invention was pure genius

The story of how the yield sign came about is a classic parable of innovation, and it happened right here in Oklahoma thanks to Clinton Riggs.

Riggs was a state patrolman and police officer from Tulsa. He reportedly had his idea for the yield sign in the late thirties when he attended Chicago’s Northwestern Traffic Institute. As part of the curriculum, he and other highway patrol officers were challenged to come up with solutions to real life traffic problems, for example the tendency of drivers to roll through intersections. There was already a yield law on the books, but people ignored it.

Riggs proposed a sign that said “Yield” that would control intersection traffic but also provide liability when drivers didn’t obey the law.

The rest of the class pooh-poohed the idea. What made Riggs think that a funny-shaped sign with just the word “Yield” would make people change how they drove? But Riggs couldn’t let his concept go.

He served in World War II and then returned to the Tulsa Police Department. When drawings and discussions failed to convince decision-makers in the police department and elsewhere that the yield sign idea would work, Riggs and his associate Paul Rice, a Tulsa City engineer, came up with a prototype.

The concept was simple. The signs were made of common materials and required no electronics. They made the signs yellow because that was the easiest color to see at night and keystone-shaped so they would be odd enough to catch a driver’s eye. There was no need to change the way intersections were constructed and no training required for either drivers or police. The signs aligned with existing laws. There was no need to change regulations that were on the books. The yield sign solution truly was plug and play.

In 1950, Riggs and Rice (without official approval) installed two prototype yield signs at the corner or First Street and Columbus Avenue in Tulsa, reportedly the most dangerous intersection in town. They waited and watched. The yield signs were so intuitive that without explanation, drivers obeyed. In interviews, many even thought they had seen the yield signs before.

This textbook tale of innovation began where all great innovations start — with a tenacious inventor who knew his market and his “customers.” Riggs had years of experience in traffic enforcement. He set out to solve a big problem for an enormous market. Think how many intersections there are in the world without stop signs. Now think about how many wrecks there would be without “YIELD” signs.

Riggs and Rice collected quantitative and anecdotal results from their beta test to prove that with yield signs, accidents at the corner declined dramatically. In 1954, the yield sign was added to the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD), and the rest is history.

The next time you see a yield sign, think about Clinton Riggs and how he so simply, elegantly and stubbornly solved a big problem in traffic safety. Then think about the people in your business, your neighborhood, your family who have ideas. Let’s make it our mission to encourage every single one of them.

Scott Meacham is president and CEO of i2E Inc., a nonprofit corporation that mentors many of the state’s technology-based startup companies. i2E receives state support from the Oklahoma Center for the Advancement of Science and Technology and is an integral part of Oklahoma’s Innovation Model. Contact Meacham at