Add two people to your daily commute. You'll not only have more backup singers to help you croon to the radio on the way to work, but you'll be saving gas, reducing greenhouse... read full tip

Add two people to your daily commute. You'll not only have more backup singers to help you croon to the radio on the way to work, but you'll be saving gas, reducing greenhouse gas emissions, and spending less money at tolls.

Commuters in New York, New Jersey, Pennsylvania, Delaware, and Massachusetts who have an E-ZPass can save up to $2 per trip with a carpool discount. If every solo commuter in those states carpooled this way for one year, the collective savings would be nearly $5 billion. Billion! That's enough to buy more than 3,000 new light rail train cars similar to the bright and comfortable trains New York City is adding to its subway system.