Sources of statistics for comparing the cost of transportation.

<ul>
<li><b>cars</b>
    <ul>
    <li>The AAA releases a yearly report titled "<a href="http://www.google.com/search?q=site:aaapublicaffairs.com+%22driving+costs%22+filetype:pdf&hl=en&safe=off">Your Driving Costs</a>" that summarizes the per-mile costs of driving.  It's nicely detailed, giving summaries for large/medium/small vehicles, and averages for 10k/15k/20k miles per year.
    <li>the IRS allows <a href="http://www.irs.gov/taxpros/article/0,,id=156624,00.html">business mileage to be deducted</a>  (included are: depreciation, lease payments, maintenance/repairs, gasoline, oil, insurance, or vehicle registration)
    <li>various <a href="http://en.wikipedia.org/wiki/List_of_carsharing_operators#United_States">carsharing organizations</a> bundle all costs into their rates (insurance, gas, etc).  However, they usually charge <i>per hour</i> rather than <i>per mile</i>, making it more difficult to use their rates to compare.
    <li><i><a href="http://www.commutesolutions.org/calculator%20resource%20list%202009.htm">more</a></i>
    </ul>
<li><b>bicycle</b>
    <ul>
    <li><a href="http://www.kenkifer.com/bikepages/advocacy/autocost.htm">9.6&cent; per mile</a> (see "Total User Costs" &mdash; I prefer to compare costs without including externalities)
    </ul>
</ul>

<h3>personal comparisons</h3>
<ul>
<li><b>May 2010, commuting from Chicago to Arlington Heights, IL</b>
    <ul>
    <li>via a WRX (the route is 15k miles a year)
        <ul>
        <li>$692 per month (including all costs listed on the AAA publication)
        <li>$401 per month (including all costs <i>except</i> for depreciation)
        </ul>
    <li>via Metra + 6 miles of biking each way: $141 per month
    </ul>
</ul>


<h3>related websites</h3>
<ul>
<li><a href="http://www.commutesolutions.org/calc.htm">CommuteSolutions.com's True Cost of Driving</a>
</ul>