Outdoor Advertising
Billboards are a part of American life, advertising for hundreds of thousands of small businesses. However, much advertising space, especially in cities, is given to multinational consumer brands.
Billboard advertising is a traditional out of home advertising format, but there has been significant growth in digital out of home advertising (billboards and place-based networks) in recent years, with about 1,500 digital billboard displays.
Traditional roadside billboards remain the predominant form of outdoor advertising in the US with 66 percent of total annual revenue. Today, billboard revenue is 73 percent local ads, 18 percent national ads, and 9 percent public service ads.
Sources: Wikipedia.org Out of Home Advertising