Baby on Board is the message of a small (usually 5 inch) sign intended to be placed in the back window of an automobile to alert the emergency services to the presence of an infant in the event of a crash. Small children are known to sometimes become trapped in footwells or even thrown from the vehicle in the event of crashes. Given this purpose, drivers should remove the sign if driving without a child on board. First marketed in September 1984 by Safety 1st Corporation, the sign became a ubiquitous fad, flourishing in 1985. Its use in the US rapidly declined by 1986 as parody imitations with lines like "Baby I'm Bored", "Pit Bull on Board", and "Mother-In-Law in Trunk" became popular, although its popularity continues in the United Kingdom (along with other versions such as "Princess on Board" and "Little Person on Board"), in Italy and in Japan (usually saying "Baby in Car", with the sign written in either English or Japanese script) well into the 21st century. The original parent company diversified into infant and child care products.
Despite waning in popularity, the signs have entered the American lexicon. In 1993, The Simpsons episode "Homer's Barbershop Quartet" featured a barbershop quartet tune called "Baby On Board". The song was written by Homer Simpson in a flashback to 1985 when Marge bought a sign, hoping it would stop people "intentionally ramming our car."
An urban legend claims that the death of a baby led to the creation of the signs. According to snopes.com, there is no truth to this claim. The founder of Safety 1st, Michael Lerner, claimed to have heard about similar signs in Europe, when in fact, he entered into a partnership with Patricia and Helen Bradley of Medford, Massachusetts, to market the signs. The Bradleys had been trying to market the signs since Patricia brought them back from Germany, where her husband was stationed. Lerner eventually bought PHOB, the company set up by the Bradleys, (for approximately US$150,000) and changed the name to Safety 1st.