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Robin Chase

Robin Chase

Posted March 25, 2009 | 02:09 PM (EST)

National Dialogue on Location Privacy: do it or lose it

With the advent of "smart" phones equipped with tiny GPS receivers, innovators, advertisers, best friends, and the government are eager to learn our whereabouts. Even without GPS, the cellphones we've been carrying in our pockets for many years now are terrifically accurate homing devices. (How else would my mom's call so faithfully find me no matter where I am?)

But you can turn your cell phone off or leave it at home; and besides, divulging your location information to a private company seems to feel ok (although the recent evidence of the duplicity of the phone companies suggests perhaps this isn't wise). However, the idea of the government tracking our cars -- the very symbol of our independence -- seems clearly outrageous. And this is exactly what is being proposed by two newly released national commission reports in order to solve our transportation financing crisis.

Fifteen years of stagnant gas taxes have eroded the buying power of this revenue source, leading to our crumbling infrastructure. And the move to fuel-efficient and alternative fuel vehicles will prove to be a fatal revenue-killing transition. The Transportation Research Board, and the a national finance commission have both recommended that the country transition to a vehicle mile traveled (VMT) tax as soon as possible. Collecting such a tax will involve some kind of monitoring of car usage. Intense public discussion is about to ensue, and location privacy will be central to the debate. This is a good thing: it is time to have this national discussion before it is too late.

Signs from existing electronic tolling systems have not been encouraging. In New York and New Jersey, E-ZPass toll data has been successfully obtained for use in divorce court proceedings. In London, the massive roadside camera infrastructure has provided a warrantless data-feed to the US government and to British police agencies. Even "anonymized" traffic statistic collection can reveal a lot about our individual movements, particularly in rural areas.

So what is the right response to these well-founded concerns about privacy? Should we expect that we won't be tracked unless the police are explicitly and expensively following us? Is location privacy a right? We think so. Can we protect ourselves simply by opposing vehicle mileage taxes? Not if we face the fact that our cellphones have the same capability. Instead, we believe it is time to attack this issue head-on, with two dovetailing strategies: legislative and technical.

Legislatively, we need to protect the rights of people to

1) Explicitly control the release of information about their movements in public space. This control must extend to both the amount of information released and the uses to which that information can be put (provided people are otherwise obeying the law), and

2) Be able to use public infrastructure (roads, trains, buses) without being coerced into releasing of private location information, i.e. options must exist to enable individuals to protect their privacy and use the service (like the ability to pay in cash instead of credit card).

The courts won't help. Recent decisions from the Supreme Court have indicated that it is unlikely to interpret the Constitution as affording protection for location privacy. There needs to be a national commission dedicated to establishing a national privacy policy and mandating that transportation infrastructure (e.g., mileage tolling, insurance premium-computation, and so forth) respects these requirements.

Simultaneously, we need to be working on the technical strategy. In order to make the legislation and its requirements effective and reasonable, there need to be practical solutions to the problem of collecting usage taxes without violating privacy (read about some here). For the specific problem of mileage-based tolling, an easy solution is to simply rely on odometer readings. Although this is probably too crude for reasonable use, it does suggest the gold standard for privacy protection:

A privacy-preserving taxing protocol should reveal the minimum possible amount of information needed to achieve the policy goal, in this case the amount of tax owed.

Basically, unless there is explicit and open discussion now about how to protect the location privacy of drivers, we're pretty sure that we will find ourselves living in a world in which there is none. Rather than reflexively opposing mileage taxes, it is far better to fight hard for a sensible national policy on privacy. It's not just a matter of privacy while driving; the threats to location privacy come from all sides in our increasingly connected world.

This posting is co-authored with Andrew Blumberg and addresses many questions raised in this earlier article I wrote on "Tax for Driving? An Economic Engine."

Photo by Gerlos.