Interesting article about "share the road" signs:
http://www.scientificamerican.com/article/antibiotic-resistance-and-share-the-road-signs-can-be-grossly-misinterpreted/
"Although often described as a reminder to motorists that bicyclists may use the travel lane, bicyclists frequently complain that motorists interpret the sign to mean that they should get out of the way" wrote North Carolina State University researchers George Hess and M. Nils Peterson.
(...)
They found that signs reading “Share the Road” had virtually the same effect on respondents' mentality as did no signage at all. But an alternative wording that appeared to at least somewhat alert people to the life and limb of bike riders did exist. “Bicycles May Use Full Lane” got more people to say that a driver should wait until it's safe to pass and then give the bike a wide berth.