"Blank walls discourage walking because they make a walk seem boring and therefore longer, and because empty and lightly maintained spaces feel less safe. Detailed, colorful places are inherently more pedestrian friendly than dismal, blank spaces, and therefore urbanistically superior."
I don't know that I've ever walked along any particular route because of the presence of a mural, but I'll concede that visually interesting spaces are of course more inviting than blank ones. Where I think Dan gets into dangerous territory, however, is where he proffers a plan for how we could fill these voids with art on the cheap:
"Every high school in America is filled with art students who would love a chance to show off their skills publicly. Metro could work out a deal with a local school: Give each art student one concrete panel and let them go wild, as part of a class project."
I hate to say it, but every high school in America is filled with art students -- most of whom produce some pretty mediocre art. I would know: I was once such a student. God forbid I'd been encouraged to go wild on my own canvas, let alone a public space where thousands of pedestrians would have to pass (and cringe) every day.
I'm probably not alone on this one, considering some commenters at GGW hopped in there to say they'd rather see advertising than high-school art. I just don't believe that an amateur-looking mural is better than no mural at all.
Besides, plenty of professional artists could use the space and the commission, even if it's just a modest one.