Two major reasons I can think of: First, most U.S. public transit, particularly in the west, is inconvenient. Cars have dictated our urban layout and it's alm

Two major reasons I can think of: First, most U.S. public transit, particularly in the west, is inconvenient. Cars have dictated our urban layout and it's almost impossible to build a city that works well for both modes of transport. (e.g. cars mean large parking-lots and, therefore, spread out establishments, which means public-transit stops cannot be located near a walkable area and must drop you off in a concrete desert, with a quarter-mile walk to anything.) Second, the behavior of riders on U.S. public transit is nearly always uncivilized and frequently atrocious.