Green Hands USA: America Volunteers

If you live in an area where public transportation is available, it could save you a pile of cash while reducing your greenhouse emissions. According to a new study by the American Public Transportation Association, the average American commuter could save $816 a month -- or nearly $10,000 a year -- by switching to public transportation such as buses or trains.

The Association came up with this pretty amazing number by looking at gas prices, monthly driving averages, parking costs, average vehicle MPG and ticket prices for public transportation, among other factors.

The actual savings depends on where you live. Using public transport to commute to New York City would save you $1,205 a month, according to the Association's numbers. At the bottom of their list, commuters in Las Vegas could save $766.

One factor driving these savings is the rising cost of gasoline, which is at least 50 cents higher per gallon than it was a year ago.

You can find public transportation options in your state and calculate your own savings here.