Beyond the gas tax

As we have mentioned before, the gas tax will eventually come to an end. The following graphic illustrates the issue.
Imagine all gasoline vehicle users pay for all transportation costs. Imagine total expenses are $100,000,000 and the total number of users are 1,000,000, and all gasoline powered cars get 30 MPG. In that case, if all vehicles are gasoline powered, the gas tax will be $0.30/gallon, in line with current costs. Now imagine, only half of all cars pay the gas tax, the tax jumps to $0.60 to cover costs, still quite tolerable, but as the gas tax rises, the number of gasoline powered cars should be expected to fall. The following image shows the expected gas tax based on the above assumptions with a varying number of gasoline powered cars on the road. Note especially this is a log-log scale. At 50,000 cars with gasoline engines (95% non-gasoline powered), the tax jumps to $6.00 per gallon (above European levels), but the last car has to pay $300,000 per gallon. The move away from the gas tax is a positive feedback system that will accelerate. A replacement is required.
GasTax
The possibility most vetted is some form of mileage tax using GPS technology. The following article from the Albany Democrat describes
Oregon’s proposal, which as the comments on the article indicates, will not come without some political struggle.
The longer version of the report is
Oregon’s Mileage Fee Concept and Road User Fee Pilot Program
along with a report by Starr McMullen and Lei Zhang on
Techniques for assessing the socio-economic effects of vehicle mileage fees

The cost of park and ride

From Minneapolis / St. Paul Business Journal: Metro Transit cuts two park and rides
One was a 288-stall lot, from the article “Metro Transit, a metropolitan-wide government agency, expects to save $17,000 in plowing and $16,000 in lighting expense for the surface lot per year, Gibbons said.” So $33,000 per 288 spaces, assuming all were occupied, amounts to a subsidy of $114.58 per parked car per year. (Divide by load factor for the actual subsidy which is higher), or at least $0.45 per day per car. This adds to the cross-subsidy from people who walk-to-transit to people who drive-to-transit. Given transit fares are $2.25 (local) in rush (or $4.50 per day round trip), this is at least 10% of total trip fares.