What driving costs other people

Economists have priced automobile externalities for decades. They disagree on the total, not on whether it is zero. Yearly figures are per vehicle: ¢ per vehicle-mile times that car’s miles. Most lines are US averages — a downtown peak is not a Kansas Sunday. The estimates below are not averaged together.

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Published estimates, not four methods of one study. Parry 2007 and Parry, new climate share a bag; only the carbon price changes. Litman adds unpaid roads, parking, and barrier effects. CE Delft is a European average, in a different unit.

What each line is

Highlighted lines are in the estimate you have selected.

What the numbers say

Data, so you can argue with it

The calculator only uses data/estimates.json. Time, place, and health are on another page; miles and mode versus Europe and Canada on a third. If a line looks wrong, check the source on that pack and file an issue.

An externality is a cost imposed on someone else — including congestion delay on other drivers. Gas, depreciation, and your own crash risk are mostly private. A two-car household is two yearly totals. Occupancy (1.52 people) does not split the congestion you impose. A peak-hour mile in a dense city is not a rural Sunday mile.