Are freeway overpasses curtailing public discourse?

Towns used to be built around public squares, which became the center and podium for all manner of public discourse. Later, buildings came first and public space became an after-thought. Worse yet, now freeway overpasses rather than public squares or plazas are often selected as the place to protest and pontificate about a political or social belief. Planner, urbanist, and Leon Krier disciple, Howard Blackson writes about this less obvious loss to an auto-oriented lifestyle: 

Our failure to cultivate the value and quality of our public spaces and public life is found in this picture of protesters and political advocates on a freeway overpass. Our cities are made up of public buildings, streets, squares and private lots, blocks and buildings. But when people want to be heard, seen, and get their message out to as many people as possible, they now gather on freeway bridge overpasses… for its on the freeways where everyone else can be found today, and not on our public street corners and squares.

Blackson goes on to point out how freeway overpasses are not the equals of urban public spaces: 

When I see people expressing their views on freeway overpasses, I see our civilization under duress or at least in transition – from gathering in the square to holding signs on an overpass bridge. These are one-way statements and this type of conversation does not facilitate a dialog and understanding. Sadly, this illustrates how far we’ve receded from what urban design guru Leon Krier teaches, “The architecture of the city and public space is a matter of common concern to the same degree as laws and language – they are the foundation of civility and civilization.”

For more of Blackson's thoughts on this topic, see the source article.