These restrictions are needed. Maybe the area covered is excessive, but I was happy that the city of Eugene responded quickly when I called about a sign that blocked my view  of traffic, making a turn on to Willamette unsafe.  A relatively short person in a small car can find her view blocked by a sign that causes no problem for a taller person in a SUV.  I don't recall what the topic was on that sign, but I think it was more of a commercial than political nature.