Yet another benefit to riding a bike - saving gasoline. There's the obvious reduction in consumption by replacing car miles with bike miles. But don't forget the increase in fuel efficiency when you do drive. How's that? Certain behaviors become inbred when you're personally responsible for outputting the watts needed to move through space.
If the stoplight ahead turns red, stop pedaling. Try to time your arrival so that you can coast through on the green and save momentum. Don't race away from stoplights/signs. It takes a lot of energy to accelerate quickly. Build up speed gradually. Slow down on hills. You're working against gravity, so it costs 4 times as much energy to go up a hill at 20 MPH as it does at 10 MPH.
All this becomes second nature on a bicycle. Strangely enough, it also works just as well in a car.