How expensive should driving be?

One study, for example, argues that quite a lot of money is used to subsidize driving. It comes up with a figure of 5.6 cents per mile from general revenue after removing from consideration taxes gathered expressly for that purpose.

The New York Times also crunched some numbers, coming up with a higher subsidy even when ignoring some of the factors included in the above study. Here's a brief excerpt of what it had to say:

What are the negative externalities of driving? To name just three: congestion, carbon emissions and traffic accidents. Every time Arthur gets in a car, it becomes more likely that Zelda — and millions of others — will suffer in each of those areas.

Which of these externalities is the most costly to U.S. society? According to current estimates, carbon emissions from driving impose a societal cost of about $20 billion a year. That sounds like an awful lot until you consider congestion: a Texas Transportation Institute study found that wasted fuel and lost productivity due to congestion cost us $78 billion a year. The damage to people and property from auto accidents, meanwhile, is by far the worst. In a 2006 paper, the economists Aaron Edlin and Pinar Karaca-Mandic argued that accidents impose a true unpaid cost of about $220 billion a year. (And that’s even though the accident rate has fallen significantly over the past 10 years, from 2.72 accidents per million miles driven to 1.98 per million; overall miles driven, however, keep rising.) So, with roughly three trillion miles driven each year producing more than $300 billion in externality costs, drivers should probably be taxed at least an extra 10 cents per mile if we want them to pay the full societal cost of their driving.