Like many automated systems we interact with today, personal rapid transit has the potential to greatly compromise privacy. Depending on details of how we arrange paying for transit, how surveillance video is archived, etc., decades from now people in some countries might discover as East Germans did after the Wall fell that the police had dossiers of their every move. Manual surveillance is expensive: the totalitarian governments of the 20th century had huge numbers of agents shadowing and photographing and listening to trivial telephone calls to learn the secrets of their citizens' lives. Digital records are far more easily compiled, collated with ubiquitous video and audio – and of course with all our online lives. Analyzing the data is much easier, too. With the computers of 2020 or 2030 it would be trivial for analysts to explore and analyze these records for a whole population; to discover groups of friends who traveled together and visited each other, find connections to anyone they consider suspicious, and track every detail of our lives.

The potential abuses of this data, from totalitarian tyranny to petty blackmail, suggest strict limits on its collection. In fact, the SkyTran site suggests that payment could be anonymous. Yet completely anonymous transport will become indefensible the first time a predator grabs a child or a terrorist group attacks and speeds away to unknown locations at 100 MPH. We are far more likely to be satisfied with the results if we design a balanced system in advance. This will require both technical means (blind signatures; secret splitting; limits on memory and communications of monitors) and organizational safeguards (open-source; challenge inspections; policies for destroying or publicizing data and the standards and responsibility for overriding them).