38 percent of cars on the road are single occupants https://www.rita.dot.gov/bts/sites/r...ection_02.html https://www.rita.dot.gov/bts/sites/r...ection_02.html one or two occupants https://www.rita.dot.gov/bts/sites/r...ection_02.html https://www.rita.dot.gov/bts/sites/r...ection_02.html