Highway warnings about traffic deaths may increase crashes, study finds

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Electronic signs are a common sight on US highways. These dot-matrix displays date back to at least the 1950s and were first used to alert drivers to changing speed limits or hazards ahead, but now you'll often see messages exhorting us to drive safely.

But targeting drivers with safety messages when they're driving may actually be counterproductive, according to a study published this week in Science. In fact, giving drivers an update on the year's road death total actually led to an increase in crashes.

Jonathan Hall and Joshua Madsen used Texas to study the impact of safety messages on highway safety thanks to a unique feature of the state—it only displays the state-wide road death count on electronic highway signs in the week leading up to each month's Department of Transportation meeting. That allowed them to compare crashes downstream of an electronic sign during those weeks with the rest of the month, as well as looking back to crashes on the same stretch of road during the years before the safety campaign started in 2012.