How many roundtrip miles to you drive to work each day?  

How many days a month do you work on average?
The national average is 21  

How much do you normally pay for gas per gallon?  $

What is the average miles per gallon of your car?  

How much do you pay per month for parking?  $

The average maintenance and tire costs are $.056/mile
(based on AAA estimate)

*Your monthly commuting costs = $

**an average Vanpool costs around $50-$70/month

2-person carpool: Average monthly drive-alone costs /2  $

3-person carpool: Average monthly drive-alone costs /3  $

4-person carpool: Average monthly drive-alone costs /4  $

$90/month = cost of 2-zone Puget Pass
good for travel on all buses across one County line or across Lake Washington.

$54/month = cost of 1-zone Puget Pass
good for all travel within one county and not across Lake Washington.

Bike = $12.50/month
(on top of the cost of purchasing a bike, plan to spend about $100/year to properly maintain your bike)

Walk = your only cost is buying walking shoes

How many roundtrip miles to you drive to work each day?

How many days a month do you work on average? The national average is 21

How many Miles per Gallon does your car go?

Your yearly Carbon Emmissions =

pounds

Source: To calculate your entire carbon footprint, follow this link:
http://www.epa.gov/climatechange/emissions/ind_calculator.html

Here's another interesting site for calculating your carbon score:
http://www.conservation.org/act/live_green/Pages/ecofootprint.aspx