Yes. In California 75% or more of the roadside billboards and bus ads are for lawyers. Typically injury lawyers. They have their own slogans and jingles.
It's actually kinda fun to look at the public transportation ads and see what they say about each major metro area. In the Bay Area most are for enterprise software vendors. In Boston most were employment ads with some obscure scientific or mathematical puzzle where if you solved it, it redirected to a biotech or software company's jobs page. In Baltimore, it was mostly for bail bonds.