In sharp contrast to the complete uselessness of “Share The Road”, survey respondents who were shown the “Bicycle May Use Full Lane” sign showed uniformly high understanding of permissible cyclist lane positioning and appropriate safe passing behavior for motorists.

“Comprehension of the familiar “Share the Road” signage as a statement of bicyclists’ roadway rights has been challenged, based on arguments that it is ambiguous, imprecise, frequently misinterpreted, and not designed for that purpose…In fact, the US state of Delaware discontinued use of the “Share the Road” plaque in November, 2013.

Source: New Study Confirms: “Share The Road” Is a Problem | Bike Delaware Inc.