The Highways Agency has confirmed that it is considering a system that will monitor traffic by tracking drivers' mobile phones.

The agency said the data will "fill in any gaps" in its traffic information, which already uses cameras and detection systems under the road.

It is understood to be assessing a system called CFVD, or cellular floating vehicle data, from supplier Itis Holdings. On its website, It describes the system as measuring and forecasting traffic flow "based on anonymously sampling the position of [mobile] phones".

The Department for Transport, under whose umbrella the Highways Agency operates, already works with Itis for information on the movement of drivers using GPS systems. But this only addressed the movement of a small proportion of drivers, and a mobile phone could achieve more, according to a report in the Financial Times.

While an individual record of a mobile phone's position is less accurate than a GPS record, this was "compensated for by the large number of mobile phones on any road, knowledge of the underlying road network and the application of statistical techniques", Itis says on its website.

The move to track even more data could prompt further fears about Britain's 'database state'. But Itis maintained that the data would remain anonymous, because mobile phone operators already ensure the data cannot be linked to individuals. Jonathan Burr, chief operating officer, told the FT: "All we know is that a phone with a randomised ID has moved between two cells."

The Highways Agency today said it would evaluate the technology, but had not made any decisions. A spokesperson added: "We have looked at the use of some form of non-personal GPS and mobile phone data as a supplement to our own fixed technology and will be carrying out further evaluation."

Meanwhile, the agency is under pressure to create an £80 million (US$127.8 million) asset management system, after the National Audit Office said last October that the system was needed as a "high priority", in order to fill in the agency's information gaps around the repair state of "safety fencing, drainage, embankments or structures".

The agency is also procuring a £200 million system to improve its intelligence and analysis on traffic data.

Its IT infrastructure is run by Atos Origin under a £75 million five year deal signed in 2008.