Studies have shown that because of more carpooling more people are suffering from second hand smoke. With the price of gas it saves everyone money when you share rides. Remember though, when you share a ride you are also sharing air in the car.
I would think that most people who drive carpools would be sensitive to the other people in the car and if anyone of them is a nonsmoker than smoking should not be done inside the car. Even with the windows open there is smoke inside and those who are sensitive to it will be bothered.
I admit it, I am a smoker, but I will not smoke in anyones car, even mine if one of my passengers is a child or a nonsmoker. I don’t need it that badly.
[...] More here: Recession Increases Secondhand Smoke [...]