Not too long ago we noted that most people in Europe and the US commute an average of 30 minutes each way. Tim De Chant dug up a treatise by Cesare Marchetti suggesting that's been true "since the dawn of human society":
Marchetti pointed out, "Walking about 5 km/hr, and coming back to the cave for the night, gives a territory radius of about 2.5 km and an area of about 20 km2. This is the definition of the territory of a village, and … this is precisely the mean area associated with Greek villages today, sedimented through centuries of history."
Marchetti—not one to think small, apparently—then used his new universal constant as a jumping off point to explore the future of tomorrow. How fast would a transportation system need to be to serve a city of 100 billion people? An average speed of 150 km/h sounds about right. Can you turn Switzerland into one giant city? Sure, so long as you run maglev trains in sealed tunnels sucked free of atmosphere. What about if you linked Paris and Casablanca with a maglev, too? "[A] woman in Casablanca could go to work in Paris, and cook dinner for her children in the evening."
The Dish 