Regardless of what any state official says, this system clearly has the ability to track where you're at. One of the functional requirements listed in the program's Final Report (p. 14) is
Zone differentiation and mileage counting. An on-vehicle device must have an ability to collect and differentiate miles driven within pre-established geographic zones, and provide mileage information to motorists.Obviously this requires positional tracking, though at what frequency I'm still not sure.
Also, let's dismiss with the notion that the state will not be able to access this detailed data. The ODOT official in charge said:
In more than one interview with the Democrat-Herald and others, James Whitty, the ODOT official in charge of the project, tried to assure the public that tracking people’s travels was not in the plans....As anyone who has ever written even a small computer program knows, you will always be able to access the most intimate data in any system so that you can debug it and troubleshoot it when necessary. Sure, there might not be nice, neat administration screens in ODOT headquarters where this data can be readily called up, but all that means is that you go to the administrator running the system, he/she logs in as a superuser, and has access to everything. At worst, you call up the programmer who built it all, and of course he knows all the ways in. Anyone who has ever dealt with a computer system of any extent whatsoever knows this -- to deny otherwise is kind of insulting.
“The concept requires no transmission of vehicle travel locations, either in real time or of travel history,” the report said. “Accordingly, no travel location points are stored within the vehicle or transmitted elsewhere. Thus there can be no ‘tracking’ of vehicle movements.”
Also, the costs look high. From p. 31 of the Final Report, the prototypes cost $662 per unit. Yes, the costs of a final program would be less, but the state does not quote a price, saying only that GPS units will likely fall below $100/chip in a few years.
So clearly this is going to cost car owners at least a couple of hundred of dollars per car, just for installation.
Station costs seem over $400/station.
The Final Report estimates (p. 32) the state's operation cost at $1.6M/yr, or less than 3% of the total mileage fee collected at the pump.
Alarmingly, "vehicle-to-pump associations" -- how often the pump recognized your car when you pulled into a service station -- was only about 80% at the trial's end (Final Report, p. 36). A 20% failure rate is huge.