Some might argue also a there’s a lesson to be learned here from graffiti, that once ubiquitous scourge of 1970s and ’80s urban life that has reemerged as a scourge but has also been brought indoors in recent decades, living often in galleries or as outdoor murals. But for all the damage graffiti does, it doesn’t impact public safety in the way a dirt bike or ATV or quad erupting out of nowhere and racing in and out of fast-moving Philly traffic can. Many riders are oblivious to the presence, the safety, and indeed, the rights, of other people to use the city’s already overburdened street and highway network.