 If you live in a city and you have to take a car or a bus, it's a fact of daily life. Gridlock. I mean freeway follies. Now, living in L.A., the AT40 staff wrestles with rush hour regularly. And while stuck in traffic, we all wondered, what are the most crowded roads in the U.S.A.? So we checked with the U.S. Department of Transportation, and they told us they have a system for evaluating the number of cars that pass a certain point on a section of road.