Politics may follow you on the road, bumper sticker study finds

Nobody wants to admit that a lowly bumper sticker can influence their behavior. But researchers at the University of Cincinnati found that drivers were far more likely to honk after being cut off by a vehicle bearing a political bumper sticker, particularly one for the opposing political party.

“Bumper stickers are a meaningful way in which partisan divides are reinforced in everyday life,” UC researchers concluded. “They have tangible impacts on road safety. Partisan bumper stickers may be mundane, but they are not trivial.”

For a study published in the journal Frontiers in Political Science, UC Assistant Professors Rachel Torres and Ben Farrer explored political polarization in apolitical settings—like driving.

They conducted attitude surveys with paid volunteers who then took part in a short driving simulation. In half of the simulations, another vehicle cuts off participants without signaling. The offending vehicle featured either no sticker or one of three bumper stickers: “Proud Democrat,” “Proud Republican” or the neutral “I love my dog.”

In the other half of the simulations, the other vehicle stays in its own lane before making an unremarkable left turn.

A follow-up survey found that drivers said they were significantly more likely to honk in the videos where the offending vehicles expressed support for the opposition party compared to those sporting stickers supporting their own party or a love for dogs.

“It activated their partisan hostilities,” said Torres, who teaches political science in UC’s School of Public and International Affairs.

“We have a unique car culture in the United States. American identity is often tied to owning a car and how you choose to decorate it,” she said. “So we wanted to ask: Has American car culture been politicized? Has it become more partisan?”

The answer, it turns out, is yes.

“These feelings are just below the surface for many people,” Torres said.

Researchers recruited U.S. adult residents who answered a questionnaire with identifying information about gender, age, race, education and partisan identity. They also completed a personality test to find out how agreeable and authoritarian they are, since both how nice and how sensitive one is to rule-breaking can be relevant to driving habits. Non-drivers were dropped from the study population.

Participants watched a short digitally animated dashcam video of a vehicle driving in the right lane of an empty four-lane road when a sport utility vehicle driving just out of frame swerves into their lane briefly before returning to its lane.

Participants were then asked on a five-point scale how likely they were to honk in their given scenario. They also took a final survey to measure their feelings toward the other driver. That survey found that partisan bumper stickers do not trigger more patience or grace toward drivers of the same political affiliation but did trigger more hostility toward those of the opposing ideology.

“We never found bumper stickers to have a positive impact. They didn’t increase people’s perceptions of their group or other groups,” she said.