Background

The British Government is giving serious consideration to the use of road pricing as a measure to make more effective use of roads. Some proposed schemes will involve the tracking of individual vehicles by satellite navigation systems, and charging drivers according to the time and route of their trip - a system known as time, distance, place-based (TDP).

Such systems raise serious civil liberty issues. In the extreme case it could be possible for security organisations (local or foreign), or malicious individuals or companies to access databases containing the whereabouts of any driver at any point in the past.

A Department for Transport report into the acceptability of road pricing schemes showed public suspicion, with 36% of respondents thinking that holding information on where drivers had travelled was unacceptable in all circumstances.

Thus in order to preserve the individual's right to privacy, and to gain public acceptance of a position-based road pricing scheme, it is highly desirable to use a system where anonymity with respect to position and time are guaranteed by the design of the system.

The Trusted Driver Model provides the solution to the privacy problem.