The Signs That Backfire

Econlife Team
2 min readApr 27, 2022


A Virginia traffic specialist thought the Black Panther movie had perfect potential for highway signs. Within weeks, his state’s interstates asked drivers, “Wakanda Driver Are You? Safety is king.”

Reading this sign, some drivers slowed down:

The goal was to “seize people’s attention.” But maybe they overdid it.

Traffic Fatalities

Because the Texas Department of Transportation showed fatality messages for one week each month, researchers had the perfect setup for their experiment. Their data indicate that within 6.2 miles of the signs they monitored, the rate of vehicle crashes accelerated by 4.5 percent. In other words, digital safety signs (below) can backfire:

Researchers concluded that the signs increased drivers’ cognitive load. Narrowing drivers’ margin of safety, the signs gave them too much to think about. Distracted, they reacted too slowly to the need for a sudden stop or drifted into another lane. Reporting the impact of the signs from August 2012 to December 2017 in Texas, the study said there was an extra 2800 crashes a year.

That takes us to the Peltzman Effect.

Our Bottom Line: Unintended Consequences

Sometimes safety regulations can create new incentives that offset their purpose. Required to wear a seatbelt, you might drive recklessly. Prescribed a cholesterol reducing statin, you could eat fattier steaks and premium ice cream. Similarly, when flood insurance is available, people build waterfront homes and when financial institutions have federal guarantees, they have an incentive to engage in riskier investing.

Whether it’s reckless driving or risky investing, our reaction is called the Peltzman Effect. I know we can say that cognitive overload is a bit different from the Peltzman Effect’s incentives. But still, we have the unintended consequence of a well-meaning initiative.

My sources and more: My go-to podcast on Saturdays, Slate Money alerted me to the Texas safety sign study. From there, I found more detail at WSJ and this paper while the Decision Lab explained the Peltzman effect. My favorite article though was about traffic sign writers.

Originally published at on April 27, 2022.



Econlife Team

Located at the intersection of current events, history, and economics, econlife® slices away all of the layers that make economics boring and complex.