text: Next, cars can cause major stress to some people. Traffic jams, animals running across the road, not being able to see due to smog, and car accidents stress people out because they are either too busy to deal with it or being scared that they might hurt someone/something or may even get hurt themselves. "When I had a car I was always tense. I'm much happier this way," said Heidrun Walter in an article written by Elisabeth Rosenthal.