It's a classic example of how concerns about the environment are independent of political beliefs. The idea that most people shouldn't depend on cars to get around is Green--almost definitively Green.
Carbon dioxide is the by-product of breathing; it has its place in nature as long as overcrowding doesn't create an imbalance between carbon dioxide and oxygen in the air. Carbon monoxide, the by-product of burning gasoline, is a toxic chemical. You don't have to know how much harm it's doing to your body or to other living things to know you don't want to breathe any more carbon monoxide than you have to. So if you don't enjoy breathing carbon monoxide, the logical first step is never to drive when you can walk, and to share a vehicle with as many other people as possible when you do drive.
The automobile industry has spent a great deal of time and money trying to give us the idea that walking is much more difficult and dangerous than it is. As I walked to the computer center this morning I was offered a lift by a nice neighbor who clucked sympathetically, "Three miles is a long walk! I don't see how you do it!" Since this nice person with good intentions would have been driving down the same stretch of road anyway, I'm glad she shared her car, saving me a little time and a little wear on my shoes...but three miles is not a long walk for a healthy person. Primary school children and people in their nineties can do it, if they adjust their expectations to tune out the commercially manufactured belief "We need to use the car to go around the block so that people will know we have a car."
For old-school, frugal Greens whose political focus is on independence, if there's a political motivation for walking, it's likely to be resisting a slick sales pitch. Some of the Old Left wanted to resist that motor-marketing propaganda because they hated Big (Privately Owned) Business. For the Old Right, the operating belief was probably "Any time anybody has to work so hard to sell you a new product as to tell you that you can't survive without something that was invented only around the turn of the twentieth century, you know that product is worth not buying."
For Creative Tightwads, being car-free is pretty fundamental. If you really need a mechanical device to move around, as a Creative Tightwad, you might buy a bicycle. Or a wheelchair. Or a Segway, although I'm told the bugs are still being worked out.
But there are people whose frustrated ego needs compel them to try to plan and control other people's lives. These people are seriously sick and need treatment, but instead, in the twentieth century, they were often granted positions of political leadership. In the United States they usually gravitated toward the Left, even though Adolf Hitler, the sickest specimen of them all, literally moved so far leftward in his thinking that he circled around to a position usually placed on the extreme Right. There were certainly instances of the "planning" form of obsessive-compulsive disorder among patriotic right-wingers, but the Old Right usually seemed to keep these people in places where they could do relatively little damage, as office managers, school board officials, and stage directors.
Being Green, I hate to admit this, but in the present century these control freaks are using Green arguments to support their schemes for gaining control over other people. As Americans re-connect with the long-buried idea that walking is normal, that most of us can and should walk five miles every day, the control freaks have discovered a niche for themselves in the idea of "planning" car-free neighborhoods.
Tip: Neighborhoods do not need to "plan" the move to car-freedom. Just get rid of the motor-marketing zoning regulations that separate stores from houses, allow people to work from their homes, and enjoy the fresh air free of charge.