If you’re looking to cut your energy costs, your garage is a good place to start. It’s easy to be gratuitous in our driving habits — to take the car around the block or forget to bunch errands into one trip. Add to that the long, solitary commutes back and forth to work, and the money starts to add up. As do the emissions: According to National Geographic, a gallon of gasoline adds 19.6 pounds of CO2 to the atmosphere.

Fortunately, it’s relatively simple to start driving less. If you’re lucky enough to have a public transit system in your city or town, try it out, even if it’s just for a crowded event where you know parking will be difficult. If you don’t have mass transit, or it’s nowhere near where you work or live, carpooling allows you to split the cost of tolls and gas.