According to About.com, cars are one of the leading causes of noise pollution:

Cars–One of the complaints of those who live in big cities or on busy streets is the disruption from the sounds of traffic. Interestingly, though, even low levels of traffic noise can be damaging to people, and traffic noise is one of the most commonly experienced contributors to noise pollution.

Fewer vehicles on the road means less noise pollution for everyone. Read the full article to learn more about the negative effects noise pollution has on productivity and health as well as what you can do to reduce those effects.