Frog Crossings

One of my professors told us that in parts of Europe (I want to say he told us the Netherlands, although I could be wrong) people have installed "frog crossings" under roads so that frogs and other small critters can cross safely. They are apparently gridded to allow some light through, and have fences on either side to direct the critters to the tunnel.

I am also interested in larger wildlife corridors across interstates. The fragmentation we are creating with major roads is severely impacting the distribution of wildlife, especially for animals that must try to cross these roads on foot. I think this is a very important step for us to take in reconnecting the currently isolated ecosystems.
(From http://en.wikipedia.org/wiki/Wildlife_crossing)