Be sure to read the whole article if you can, some interesting info towards the end about roadcrews removing these signs while leaving up the "Support the Troops"-type signs.
http://www.boston.com/news/local/massachusetts/articles/2006/07/25/overpasses_become_activists_podiums/It takes only a bedsheet and 18-gauge wire for Bruce Macdonald to stir road rage in some motorists. For eight months the Cambridge lawyer has been stringing homemade banners from highway overpasses, including those crossing Interstate 93 and Route 128. His neatly painted messages usually take short jabs at the Bush administration or the war in Iraq.
Like noxious fumes and traffic snarls, a well-placed road sign can't be ignored by a driver, he said. Tens of thousands of cars can stream beneath an ``Impeach" or ``U.S. Out of Iraq" banner before it is ripped down, usually by a passerby or road crew. ``If they stay up a day they're doing well," Macdonald said. ``Some people get upset ." Macdonald, 59, is one of an increasing number of ``highway bloggers" -- loosely connected activists who favor bridges over websites as posting places for their antiwar slogans. They say it is an easy, inexpensive way to reach large numbers of people, especially those who may not be receptive to their opinions.
While highways have long been used to publicize everything from political candidates to marriage intentions, after the disputed 2000 presidential election a small group of self-proclaimed ``freeway bloggers" began plastering California overpasses with signs criticizing President Bush. Since the Iraq war began, the campaign has gained popularity nationwide, especially on the East and West coasts.
Patrick Randall, a pseudonym for the California man cited by several local highway bloggers as their inspiration, said in an interview that he considers major thoroughfares ``rivers of humanity." They allow him to reach a captive audience with roadway-reading material more stimulating than ``Happy 50th, Carol" or ``Huge yard sale, next exit!"