Design that changes places/people

There's a story in Malcolm Gladwell's "The Tipping Point", I think, which tells about an experiment in the NY metro. For a period of time all metro cars which had been "vandalized" with graffiti and private messages were regularly cleaned and made too look nice. The results showed a 10-30% decrease in crime rate in the stations and cars which were made part of this experiment [if I identify the book wrongly, please correct me].
The experiment speaks to the power of a different environment on behaviour and maybe is a precursor to the idea of design which improves society.
I have a friend who is involved with design and looking to conduct a similar experiment. We thought about re-designing a public environment and monitoring the change in behaviour of the people in that environment. The current candidates are a railway station waiting room and the library of a school.

I would like to ask if anyone has any other ideas and also if they know of a place that would willingly become involved in something like this.

The image here is of an Ingo Maurer lamp [ I think it has something to do with the post, design, and changing the way one feels about stuff :-)]