This is a fascinating experimental app: it lets you explore traffic conditions around the world by picking a start point and seeing where you can get from there in ten minutes, either by car or on foot, at different times of day and week. It's kind of hypnotic to play with.
To use it, go to http://www.flaviogortana.com/isoscope/
. Click on a point on the map to set your seed spot, and use the controls at the bottom left to set the departure weekday and hour. My one quibble with this is that it focuses on a 10-minute travel time: that's great for looking at extremely dense cities like London or New York, but it's a lot less informative for places like the Bay Area, where a 30-minute radius would be much more interesting.