Is Driving Downtown a Conspiracy

Why do you think we put two cars on their paths down the road facing each other, with usually just a yellow line painted between them with the idea not to cross it?

Why do schools have normal streets in front of them, rather than a huge lawn of protection from cars? And why don't downtown areas not have cars, even if for only a few blocks? The traffic is always stupid to deal with, anyway. And there are more of us born everyday. So how come there aren't 'Traffic-free Zones'?