From Michael Graham, City of Tucson Public Information Officer, responding to an email I sent to Maximiliano Torres, the point person for City of Tucson Modern Streetcar Project Business Outreach:
The Federal Transit Administration project security and safety requirements include visibility into and out of, as well as around a construction site. Allowing objects, posters, streamers, signs to remain on the fences obstructs visibility into and out of the construction zone. The fencing is a traffic control device and there are restrictions against placing items on traffic control devices.
An email from the City of Tucson was sent to David Aguirre at 2:35 p.m. yesterday informing him that the contractor would be removing the artwork, saving it, and returning it to Mr. Aguirre to redistribute to the artists who made the artwork.
Of course, one would have to imagine that keeping the fences art free might be a challenge in the long run, but time will tell.
This article appears in Jul 5-11, 2012.

So construction workers must be able to see pedestrians walking on the sidewalk?
How moronic–
Many times construction sites are fenced in with plywood, with only the occasional small
opening.
C’est des conneries!
Your tax dollars at work. Don’t worry taggers … uh Urban Artists will have “art” back up soon enuf. All looks the same to me.
BULLCRAP
They have the mesh on construction fences so you can’t see what they are doing
WHATS THE DIFFERENCE
WASTING TAX DOLLARS…….AGAIN ! !
Thanks Mari for the effort.
At least I enjoyed the artwork – the mark making was excellent in most, the images, good! First Amendment, Freedom of Expression reigns, no? One of those damn-fool, esoteric concepts I came searching for… and continue searching.
What is wrong with leaving that art work up? It was not obstructing as I could easily see through and around the images – I viewed it 2, 3 times. Just more 1% nonsense foisted on that vague concept of “We, the People.”