freeway blogging
n.— «It’s a new American graffiti—the art of freeway blogging. Americans driving to work or the mall are increasingly being confronted by guerrilla art, or political messages, strung across freeway bridges or staked on verges and embankments.» —“Sign of the times: dissent on America’s highways” by Ros Davidson Sunday Herald (Glasgow, Scotland) Sept. 4, 2005. (source: Double-Tongued Dictionary)