While everyone on here advocating for fewer cars and more alternatives (walking, biking, public transportation) is correct for all the usual reasons (environment), there are several issues that make it harder in Houston:
1. The heat in the summer
2. There isn't mixed use housing. Walking by restaurants and cafes and people in NYC is a pleasant experience. Walking over sidewalks in the heat without a person in site is not as pleasant.
I think if they start more mix use housing (several brave souls try every year), and as they become successful, we will see more walking in the good seasons.
I know, it feels like we don't have that kind of time, but hopefully we can plant more trees in the meantime to slow it all down.