We don’t have a hybrid vehicle, and can’t afford to buy one right now. So, since my parents need to drive to work and drive me to school, it seems like reducing the amount of gas we use isn’t really possible, is it?

Of course it’s possible! There are numerous other ways to reduce gasoline usage short of switching to a hybrid or electric vehicle. Carpooling, biking and walking are three excellent ways to significantly reduce gas usage, as are telecommuting for work and riding public transportation. Also, combining trips to school or work with routine errands cuts down significantly on miles traveled.