These are typically 4 metre tall poles with sensors and antennae on the top, such as the one pictured here, located on the A5 near Tamworth.
Similar devices can be seen attached to bridges on dual carriageways and motorways (photos at bottom of page).
Many drivers are concerned that these are speed cameras, and although this is true in a sense, they are not speed cameras in the usual meaning of the phrase. They are in fact part of the TrafficMaster vehicle information system.
TrafficMaster are obviously aware of drivers concerns, as some sensors on motorway bridges carry notices informing that they are NOT used for speed control, so great was their fear that frustrated drivers might damage them!
The Traffic Master system monitors traffic flow speeds. This information is then broadcast from the antennae mounted on the same blue poles, or from nearby posts, to subscribers' in-car TrafficMaster receivers.
How it works
Trafficmaster claim that the system stores only part of a vehicle's registration number. They state that only the middle four characters are stored. Since most registration numbers in the UK have seven characters, there is no such thing as the middle four! The system must therefore be able to read the whole registration number in order to extract the 'middle four' characters.
Trafficmaster further claim that only a sample of vehicles is used.
It it obvious that if a given vehicle is chosen at random by one sensor, then the next sensor must read all the registration plates passing it in order to catch the vehicle. Since vehicles travel in all directions, all sensors must read all vehicles for the system to work. It may be that only a sample of registration numbers are stored for average speed calculations, but the system clearly must have the ability to capture all vehicles.
When a vehicle passes the next sensor, the time taken to travel between the two sensors can be calculated. As the distance between sensors is known, the average speed of the vehicle can be calculated. By constantly calculating the average speed of a sample of vehicles, congestion can be detected. This information is then transmitted to in-car TrafficMaster receivers.
The registration number is then allegedly discarded by the system. It is not clear what happens if the vehicle does not reach any adjacent sensor in a given time (i.e. it completes its journey or transfers to a minor route with no sensors).
Concerns for the future
Although the TrafficMaster system is entirely useful to drivers at this time, there are serious concerns that technology such as this could be abused in the future, to create a nationwide speed trap.
For example: suppose you are travelling from London to Leeds. As you join the M1 your registration number and time is logged, when you reach Leeds the same occurs, your average speed could then be calculated, and if it exceeds the speed limit, the information could be used to prosecute you.
Whether Trafficmaster would ever allow their system to be used in this way is open to debate, there being the strong probability that many potential customers would not subscribe to the service. However, similar technology could easily be abused by another company.
Some blue poles are co-located with Gatso cameras. This is probably a matter of convenience (power is already there) but does seem to indicate a level of collusion between the authorities and a private company which may be worrying.
|The Trafficmaster system should not be confused with the SPECS digital speed cameras, which resemble standard surveillance cameras with spotlights either side, whose support posts are also painted dark blue.|
The cameras themselves are now painted yellow, which has earned them the nickname of 'yellow vultures'.
Photographs of the SPECS cameras on the A610 in Nottingham can be seen in
Other web sites for further information:
An alternative sensor mounting arrangement located on a bridge over the A38 Sutton Coldfield bypass. The antenna post can be seen in the background.
|Example of a Trafficmaster camera array on a bridge over the M69 near Leicester.|
This array was installed in July 2007.
|Here you can see the three cameras covering each lane of the motorway, with the control box and poles in the background. The cameras are merely attached to the railings on the bridge.|
The purpose of the poles on the control box are uncertain, one is probably a transmitter to send data to passing cars, the other may be an environmental sensor to detect for example, rain.
This close up of the back of a camera reveals it to be manufactured by PIPS Technology Ltd of Eastleigh.|
The model number is P362, and this one is serial number 6128.
PIPS describe the P362 as a 'Compact ANPR Image Capture System'. It has built in infra-red illuminators.
|This photograph shows an additional black sensor adjacent to the camera nearest the hard shoulder.|
It's purpose is unknown, but it could conceivably measure road conditions such as temperature. The box on the end of the arm does not seem to point at approaching traffic.
|This close up shows how the trunking from the cameras and control box feed into purple trunking that goes underground.|
We assume that this is the same purple trunking that has been buried alongside all motorways, and is used amongst other things to carry data to the roadside signs that are all too often used to display nannying messages.
|A close up of the control box shows how worried Trafficmaster are that their system might be attacked by people mistaking them for speed cameras. The label says:|
Trafficmaster ™The claim that the devices are 'not a camera' contradicts PIPS description of them.
Traffic jam early warning
system for motorists.
NOT A CAMERA
NOT A SPEED TRAP
Telephone 01234 759100
|This photo shows the camera over lane 1 and the trunking running along the railings back to the control box.|
|A close up of one of the trunking junction boxes, and the camera attachment to the railings.|
This array is located on the Croft Lane M69 overbridge near Thurlaston, Leics. SP501976.
|Photographs © Pro-Motor Ltd 2007|
The Highways Agency are now installing cameras on many trunk roads and motorways that are similar to the Trafficmaster cameras, but are coloured dark green. These are said to be for 'traffic monitoring purposes', we believe they are connected to the National Traffic Control Centre.
In 2007 we were made aware that these cameras are part of the Highways Agency's NRTS system, which is capable of being used to support road pricing.