It's pretty hard to do good public transportation in a place like Houston. I've had forty-mile commutes in the past, and once you get that far out, you get that nasty superlinear expansion of area covered. The closest Houston could ever get is park-and-ride, i.e. re-locating the sea of asphalt, because buses are too dang slow. Not to mention walking is absolute misery due to weather from May to September.