The shaving cream company Burma-Shave ran an ad campaign from 1927 to 1963 that consisted of sequential billboards along highways. There would usually be six billboards in total, each of which had a segment of a rhyme on it.
The rhymes usually promoted Burma-Shave's products, but the company also did a series of public service messages regarding traffic laws and safe driving. The signs were removed when the company was sold to Phillip Morris in 1963. The brand was sold to American Safety Razor Company and reintroduced in 1997, but as of May 2015, the iconic signs have not been used again.