These straps are designed so that people who can't reach the high horizontal bus and subway bars and aren't close to a vertical bar, or simply would rather not touch these bars, can have a fixed point to hold onto. They don't seem particularly green in themselves, but the fact that they can make the public transportation experience better and more attractive to some people is very treehugger-like. There are three different models and a couple of accessories: The original, straightforward one, The "DX" model with a D-ring, and the reader sling which allows you to free your hands so that you can hold a newspaper or a book. You can read testimonials of Transtrap users here. I particularly enjoyed this quote: "People around me seemed to be wondering why there's only one strap?" ::Transtrap