I couldn't believe the massive amounts of graffiti off the freeway in North Pleasanton. I moved from Fremont to Pleasanton because I saw this happening along 880 in Fremont. After it happened in Fremont, I notice the spiral affect it had on the areas surrounding those parts of the freeway. More spray painting on fences in the neighborhood, more pitbulls running around, more police cars called to houses (not sure why, but police car presence was more frequent). All I can say is that Pleasanton should clean this up ASAP as it does lead to more detrimental behavior (I've witnessed it firsthand in my old Fremont neighborhood).
Just read "The Tipping Point" by Malcolm Gladwell. It has been proven that people will behave worse in "trashy" neighborhoods then they would in "nice" neighborhoods (i.e., think of the general population and how they would behave in a church as opposed to a major sporting event).
My suggestion is to plant freeway ivy (or similar plants) to cover the walls and force taggers to go elsewhere as perpetual painting over graffiti is not the answer either. Freeway landscaping is the answer...I hope someone in our city government reads this.
PS - I know I'm gonna take some crap for my "pitbull" comment - but statistics show that while these dogs may NOT bite more than other breeds, they do maim or kill more (when they do bite)...so no, I'm not a proponent of ownership of these dogs. I think pitbull ownership is a status symbol and people need to get over it. I don't think the risk warrants it.