From the mid to late 1980s, the most ubiquitous road sign didn’t advise you to stop, obey the speed limit, or be mindful of crossing deer. Instead, it was diamond-shaped, used a black-on-yellow color scheme, and came with a stern warning for nearby drivers: There was a baby on board.

Safety 1st

The suction-cupped alerts that stuck to a car’s rear or side windows were originally designed to notify surrounding traffic that an infant was in their midst, the idea being that drivers would either slow down or take note that a fatigued or distracted parent was operating a motor vehicle ahead of them. In the summer of 1985, barely a year after its debut, the Baby on Board sign had been affixed to more than 3 million cars, with 500,000 being sold each month.

It was a windfall for former real estate investor and Brookline, Massachusetts resident Michael Lerner, who spent $65,000 of his own money to start Safety 1st, a child-focused consumer brand that marketed everything from poison alert labels to soft faucet caps so that babies wouldn’t hurt their heads in the tub. Lerner, who had no children of his own, recalled feeling anxious as he drove his 18-month old nephew home from a family gathering in a congested traffic area; he subsequently obtained the rights to Baby on Board from two sisters, Patricia and Helen Bradley, who had seen a similar sign in Europe but didn’t know how to peddle it to prospective buyers.

Neither did retailers. Lerner spent much of his time trying to convince department stores that the signs belonged in the infant section, not their automotive display: He believed the product was a safety device, not a novelty. The claim fell on deaf ears until he met with a buyer for the now-defunct Bradlees chain. The store was making an aggressive push for child car seats and felt Lerner’s pitch fit their strategy perfectly.

Once Bradlees began carrying it, other stores like Sears and Toys "R" Us followed suit—and by 1986, the distinctive yellow signs had become as common as a spare tire.

While Lerner was profiting handsomely, he was seeing only a fraction of the car sign industry's total revenue. Once Baby on Board caught on, it became easy for companies to manufacture parody replicas: Baby Driving, Grandma on Board, Ex-Husband in Trunk, and Illiterate on Bord were all snapped up by more cynical drivers who felt the original sign was silly to suggest they'd be driving aggressively if not for the warning. At one point, the knock-offs outnumbered Lerner’s sign by five to one on roads in the New York metropolitan area.

Safety 1st

Lerner and his satirists had one thing in common: road safety experts had extreme reservations about the signs, which could potentially obstruct the driver’s view through the rear window. While some states approved them providing they were stuck to the lower half of the glass, others were more aggressive. North Carolina law insisted nothing be placed on the window; Maryland had police officers giving drivers a $30 ticket for the infraction. In 1986, the Insurance Information Institute declared the signs posed a hazard for drivers who could become distracted by trying to read them, prompting a traffic accident. They also expressed concern rescue workers could risk harm by trying to extricate a baby who may not even be on board at the time of a collision.

Lerner dismissed the phantom-baby stigma, insisting the sign was designed to be removed when the infant was absent and felt it contributed to more responsible driving. While it was impossible to discern whether it actually made a difference, the parodies certainly did: Baby Carries No Cash and other jokes helped contribute to window decal fatigue, prompting Safety 1st to focus on other products like bath seats and door signs that could tell solicitors a baby was asleep inside. In 2000, Lerner sold the company to Dorel for $38 million. In 2014, the owners estimated more than 10 million signs had been sold.

One of them was purchased by a young man named Freddy Franco. According to an April 1987 report in Florida’s News-Journal, Franco was driving on Interstate 95 when a police officer spotted the sign and pulled him over. After growing suspicious of Franco’s nervousness, the officer searched the vehicle. In addition to being in violation of a state law banning anything from rear windows, Franco also had 15 pounds of cocaine hidden in compartments. There was no baby.