You're not going to get the benefits of reducing congestion unless drivers KNOW what price they are paying for driving.
This thing needs to be able to display three things to the driver at all times:
(1) The current rate per kilometer (or mile) being paid. This allows people to complain that they are being taxed for driving on their own lawn. It also lets them know about the expensive peak times, so they can avoid them.
(2) The taxometer reading: the total accumulated taxes for this unit. The value never goes down (like an odometer, and except for the inevitable tampering), unless it rolls over, which should not be possible (or at least not likely) within the period between readings (how much would the taxes be on a car driven on the most expensive freeways 24x7 at the speed limit between the monthly readings? Make sure it won't overflow with several times that amount.). You pay the difference between the current reading and the last one when it gets read for tax purposes.
(3) The trip taxometer. Like a trip odometer, it increases with the taxometer but it can be reset to zero at any time by the driver, so the driver can reset it before a trip and read it at the end, comparing the taxes on alternative routes. This reading is not used in the tax calculation. It is only there for the convenience of the driver.
You also need (4) the serial number of the taxometer, which never changes. Guess what: this is the ONLY information you ever need to take out of the taxometer. Route info never needs to be saved, which will probably remove the REAL reason behind these schemes.
Explain why this is different from a gas tax or mileage tax, which accomplish the same thing with a lot less equipment.
Gordon L. Burditt
