The idea, as described in Eric Pryne's article "Oregon to test mileage tax as replacement for gas tax" can be summarized in a few key points:
- As consumers buy more fuel efficient cars, they'll use less gasoline.
- States collect taxes from gasoline, so if less gasoline is sold, the state will collect less tax revenue, all else being equal.
- States can ill afford a drop in revenue as those funds pay for road repairs.
- Thus we must find a new way to tax drivers to make up for this lost revenue.
When examining any tax, there are two criteria you can use to determine the impact that tax will have:
The Net Amount of Revenue Collected
This impact is straight forward. Once you pay for all the expenses related to collecting the tax revenue, how much money will you have left over? Under this criteria, this new tax looks like a loser. Expensive new technology will have to every new car in the State as well as every new gas pump. If 100,000 new cars are sold each year in Oregon, $23 million dollars will be spent in specialized GPS devices. While the government may require that the individual consumer pick up the tab, this is still lost revenue for the government. Instead of requiring the consumer to buy a $225 device, the state could add a $225 tax to every new car sold, thus having the money flow to the State and not to the GPS manufacturer.
The Distortions Caused by Taxation
Taxes are distortionary in the sense that they alter behavior. High income taxes are known to cause employees to work less and high capital gains taxes are a deterrent to investing in the stock market. These distortions are not always negative; often governments will introduce new taxes because of the distortions they cause. High taxes on cigarettes are often promoted as a way to discourage youth from picking up the habit.The distortions caused by gasoline taxes are threefold.
- High gasoline taxes reduce the amount people drive
- High gasoline taxes increase the marginal cost of goods shipped by truck
- High gasoline taxes cause people to buy more fuel efficient cars
When we consider these distortions, we see that the mileage tax is a poor substitute for the gas tax. It has all the negative features of the gas tax, such as decreasing the number of trips taken and increasing the marginal costs of products shipped via truck. It, however, does not have the positive impact of causing consumers to buy less polluting cars. Any proposal that has less benefits but just as many drawbacks as existing methods can hardly be seen as a positive change.

