The cameras, which combine number plate reading technology with a global positioning satellite receiver, are similar to those used in roadworks.
The AA said it believed the new system could cover a network of streets as opposed to a straight line, and was “probably geared up to zones in residential areas.”
The `SpeedSpike’ system, which calculates average speed between any two points in the network, has been developed by PIPS Technology Ltd, an American-owned company with a base in Hampshire.
Details of the trials are contained in a House of Commons report. The company said in its evidence that the cameras enabled "number plate capture in all weather conditions, 24 hours a day". It also referred to the system's "low cost" and ease of installation.
The system could be used for "main road enforcement for congestion reduction and speed enforcement", and could help to "eliminate rat-runs" and cut speeds outside schools, it added. It could also reduce the need for speed humps.
The development of speed cameras has raised concerns about expanding state surveillance.
The Home Office said it was unable to comment on the trials because of "commercial confidentiality".
The AA said it would watch the system “carefully” but it did not believe there was anything sinister. “It is a natural evolution of the technology that is out there,” a spokesman said.