While I was in Tokyo this week, I asked a few people what it's like to drive in what is one of the world's largest cities. They had a whole list of complaints: traffic is horrible, the price of gas is astronomical, parking is impossible. Which helps explain why Kei's are ubiquitous in the Japanese capitol.

If a road is constantly clogged with traffic, it must be too small. Build more roads and you'll have less traffic, right? Not necessarily.

In a study that at first glance doesn't seem to make much sense, three scientists have discovered that drivers choosing between multiple routes to reach their destination most quickly can actually end up slowing everyone down. Limiting their options by closing off certain streets could actually reduce congestion.

City officials in Delhi are sparring with activists and transportation policy wonks over a ubiquitous site on the streets of India -- cycle rickshaws. The city banned the three-wheelers from many areas three years ago, and though the ban was recently overturned, everyone says the fight is far from over.