It is completely ridiculous that people who live far from school, with no bus service, or have disabilities which prevent them from walking are getting defensive.
Obviously, some people have no choice but to drive.
Obviously this thread is not directed at you!
Equally obviously, there are a lot of people who are too lazy to walk or bike, and could very easily do so.
Slightly less obvious are the people who live a little further away (say, 1-2 miles), or on a road which is slightly tricky for biking on (like mine, a small country road without a bike path, perfectly fine for biking, but you have to be a bit cautious). Those people could afford to look at the bigger picture- the impact that their driving has on the environment, local congestion, and their children's health; those people could think about making an effort to walk or bike at least some of the time, for a whole lot of reasons which have been eloquently written about on here already.
Yes there are some people with hidden disabilities who need transport, but for every person with a real need for a car for a short journey, there are hundreds of people who just don't care, don't think about their actions, can't be bothered, or have the attitude: "I know I should walk, but this one little car trip doesn't actually matter".