Gasoline prices at the local gas station nearly reached $4 a gallon a couple of months ago. I think I paid $3.79 for regular unleaded. The price is back down to about $3.19, but even so, that means it costs over $30 to fill up the 10 gallon tank in our Honda Civic.

Every gallon we can save is $3.19 in our pockets. That in itself is enough to make me want to conserve fuel by driving a fuel efficient car (and by driving the speed limit). It's a bonus knowing that the fewer gallons of gas burned mean fewer CO2 molecules released into the air. Each gallon of gas burned releases about 20 pounds of CO2.

Consider this:

A car that gets 20 miles to the gallon will consume 750 gallons of gas to travel 15,000 miles. In the process, the car will produce 15,000 pounds of carbon, and costing about $2,400 just for gasoline!

A car that gets 30 miles to the gallon will consume 500 gallons of gas to travel 15,000 miles. In the process, the car will produce 10,000 pounds of carbon, and will cost about $1,600 to fill up with gas.

Our cars get 40 miles to the gallon, so driving 15,000 miles consumes 375 gallons of gas, releases 7,500 pounds of carbon and costs us $1,200 for the gasoline.

Just think, if the average fuel efficiency of cars on the road were increased by 10 miles per gallon, we would save hundreds of millions of gallons of gas each year!

And even if every car improved its mileage by 1 mile per gallon (which almost everyone can do just by driving the speed limit), we would be releasing millions fewer pounds of carbon.