Hospital visit, next exit? Roadside billboards are the driving distraction you haven’t heard of: they mess with your mind—and your right foot—long after you’ve refocused on the road, new research shows. In the study, researchers at the University of Alberta asked 30 adults to hop into a driving simulator and react to different types of billboards. The boards featured both positive and negative words like “joy” or “stress,” as well as target words the drivers were told to look out for, such as “cat” and “lion.” If a driver saw a target word, he was supposed to press a button. The results: When billboards featured negative words, drivers tended to slow down and veer from their lanes, according to the study. The drivers were also slower to spot the target words, which indicates that the negative language was distracting, says study author Michelle Chan, a PhD candidate at U of A. On the other hand, positive words caused drivers to push the pedal to the metal after they’d passed the billboard. Chan’s explanation: Research has shown that your emotions affect your attention and decision making skills. Negative language is more emotionally charged, so it absorbs more of your focus, she says. Meanwhile, the arousing effect of positive emotion actually broadens your focus and energizes you, which could explain the increase in speed. And it’s not just words, Chan says. Negative or positive images are likely to distract drivers in similar ways. Ironically, those frightening billboards showing car wrecks and warnings about the dangers of drinking or texting while driving may actually distract you into an accident, the research suggests. How can you protect yourself? You’re already halfway there. Just knowing that billboards cause distraction can help drivers keep their minds (and eyes) on the road, Chan says. Billboards are especially dangerous in urban areas and on busy roadways, and Chan says she hopes policymakers will enforce stronger regulations regarding where ads can be placed. In the meantime, lowering your visor to block elevated ads could also help. More from Prevention: The Driving Habit You Need To Break Questions? Comments? Contact Prevention’s News Team.