You may have chuckled (or groaned) at the funny safety messages that pop up on America’s highways. Maine, for example, recently put one up saying “Little Known Fact: Snow Is Really Slippery,” while Minnesota had one that said “Let’s Go Barbie / Buckle Up / Yes, You Ken!” State governments have long enjoyed creating snarky or silly signs—often inspired by pop culture or holidays—to encourage caution. But in December, the Federal Highway Administration tried to tamp down all the humor, warning that trying to make drivers laugh could distract or confuse them. Research on the effectiveness of funny signs yields conflicting findings, but state officials argue that drivers pay more attention to them. Still, some states say they’ll follow the federal guidance and be mindful of what messages they put up. “Our goal is always to create attention to safety, and that’s what these signs are about,” says New Jersey Department of Transportation spokesman Steve Schapiro. “It’s about making sure people read them, remember them, and drive safely.”