Roadless

This morning on my bicycle commute I was listening to the Science magazine podcast which is no bayblab podcast but it's good enough for commuting. On the latest episode I was informed that there is no place in the lower 48 states of the United States where you can get more than 35km from a road. Thirty-five kilometers away from civilization is isolated but I still found that stat pretty shocking. The above map shows the 'roadless volume' of areas in the united states. I ganked it from the origonal article in Science magazine (high priced subscription required). 'Roadless volume' meaning area times the distance from a road such that a city block would look like a pyramid with the point being in the center since it is the furthest from the roads. I wonder what this data looks like for a country like canada with large uninhabited areas. There is also a video in the supplymentary material but it's quicktime so I can't get it to work. I have to say that the United States does an excellent job with their parks, (they are large and well managed) and there is actually an effort to preserve roadless area in the US.