Motor Fuel Taxes: Cost per mile

The American Automobile Club's annual "Your Driving Costs" indicates that a motorist spends between 6.9 cents to 10.8 cents per mile for gasoline. The study used $1.939 per gallon as the cost of fuel and EPA mileage figures weighted 60% city and 40% highway.

The American Petroleum Institute indicates that the average tax on gasoline is $0.42 per gallon. Add 6 cents per gallon for diesel. The American Road & Transportation Builders Association reports 83.9% of gasoline revenues go to highways, 15.5 to mass transit and 0.5 to other trust funds. (adds to 99.9, round off?)

If ALL the gasoline tax were dedicated to roads and ALL vehicles were using 10.8 cents of gasoline per mile, the gasoline tax collected would be $0.0234 per mile. Two plus cents per mile. Gives another meaning for getting your two cents worth?

Traffic engineers report a busy road as having an average of about 1,000 cars per lane-hour on an annual basis. About $23.39 per lane-mile hour is gasoline tax. Using 8,766 hours per year (remember leap year?) That amounts to about $205,000 per year per lane-mile. About a fifth of a million dollars. Using 83.9% for highways and ALL cars at $0.068 per mile would produce annual revenue of $111,346. So a busy road produces somewhere between a tenth and a fifth of a million dollars per year for each lane-mile.

If roads were designed to reduce stop and go, for instance, roundabouts instead of traffic signals, the mix of city/highway driving would reduce the amount of gasoline burned, and the tax collected.

A busier road would produce more gasoline tax revenue, a less busy road would produce less.

Which brings us to the question of how much a lane-mile costs. A road lasts about twenty years. Major costs are the road itself and interest payments. Localities have to borrow money to build the roads. Bonds are a form of loan. Conservatively, one-third of the life cycle cost will be interest on the loan, two-thirds will be the right of way, construction, maintenance and operation. Some of you accountants might want to check my future value of money assumptions. Remember, I'm looking for back of the envelope numbers, not pennies.

Over twenty years, a busy road generates between $2 million and $4 million per lane mile. As long as the road is busy, and the assumptions hold, roads with life cycle costs less than $2 million per lane-mile life cycle cost will most likely "pay their way". More expensive roads will have to "rob Peter to pay Paul".

What are the operating targets?
1. Keep the road busy 24/7. Objections? Not in my back yard.
2. Shave peaks. Move congested traffic to less congested times, or less congested places. Objections? That's not my job.
4. Reduce the number of acceleration cycles in the average drive. Objections? Que bono?
5. Check the tax revenue stream for "leakage". Objections? Not my job.
6. Sit in congested traffic and complain. Objections? None, we are all pretty good at congestion sitting and getting more practice every day. Must be the national pastime that has replaced baseball.

dickboyd@aol.com