Recently I argued that there was a "Death Valley of Commute Options" between transit and driving, If you're sick of the crowding on transit it costs a lot to upgrade to driving, and if you can then no longer afford to drive it's a big drop back to transit.
I was a little sloppy with the math behind the car options, and commenters like Christopher Parker and Joel Davis sorted me out. So here's the new version of my chart:
As you can see on the spreadsheet, I've included gas, parking, a car loan and insurance for a total cost of $24.48 each way. Parker claims that "the public uses its perception of the cost which is gasoline only," so I've provided a figure for that too, "Perceived car," which is $15.82.
Alon got ahead of me and pointed out that many civil (and uncivil, PDF) servants get free parking. In addition, most car owners park for free on the street, which would bring the cost down to $12.81.
If we do that, Death Valley almost disappears! But what if you don't live and work in the relatively small areas of the city where an express bus or commuter rail commute makes sense?
There's Death Valley again, especially if you don't have free parking. And what if you can't drive because of disability, prior conviction, or just wanting to be extra careful not to kill innocent people?
Humungous Death Valley, and the taxi option just seems like a silly luxury. That's why so many people drive in the city. The easiest way to get those people out of their cars is to offer a premium commute option, or at least let someone else try.