Actually, your property line is usually the center line of the street. From the center line of the street back toward your house will be a certain measurement (20, 30, 40 feet) that is an easement for the road and sidewalk. That area is for the "good of the public" and generally not under the control of the landowner. I believe that as long as you remain in this area you won't be found in violation of being on school property with a firearm. Any in the legal field wish to chime in on this.
im not versed enough to disprove your post, but I do not believe you "own" the road and are being kind enough to let the city use it.