It’s not just cars. It’s plastic bottles. It’s CDs and DVDs and records. It’s paint. It’s film. It’s diapers. And thousands of other products.
If you want to make a difference, walk or ride a bike. Stop buying bottled water. Never, ever let anyone put your purchased products in a plastic bag. If you want to punish the oil industry, use less of their product. Giving your money to Exxon instead of BP doesn’t change anything.