Highways Agency

Collection of Traffic Information

We collect information from a variety of different sources, both human and technology-based.

These include information from electronic loops in the road and Automatic Number Plate Recognition (ANPR) cameras as well as information gained from our 250 operational partners.

Traffic Flow Monitoring Equipment

You will be able to spot our traffic monitoring stations when you are driving around the motorway and trunk road network. Many of them are olive green poles with a square base and a rectangular flat panel on the top.

The flat panel on the top is a solar panel which provides the electricity to power the monitoring station. There are over 1500 of these across the country. As vehicles pass the monitoring station, the electronic sensors buried underneath the road measure the average speed and flow of the traffic. This information is then transmitted back to the National Traffic Control Centre at five minute intervals using digital mobile technology.

This dedicated monitoring system is also supported by MIDAS (Motorway Incident Detection and Automatic Signalling) which is used to detect queues on the most heavily used sections of motorway and warn drivers using variable message signs.

Automatic Number Plate Recognition Cameras

We also use Automatic Number Plate Recognition (ANPR) cameras to help monitor average journey times. We have over 1000 ANPR cameras at 480 key locations across England. When you go past the cameras, your number plate is logged and then changed into an electronic tag. By matching these tags as you pass other cameras, we can see how long it is taking you to get from one location to another. This helps us quickly identify congestion.

We use the electronic tagging system so we cannot identify individual vehicles or vehicle owners. At no stage during the process do we have your number plate and all information is deleted after a few hours.

The ANPR cameras are painted bright green and are usually mounted on bridges or on poles at the side of the road. They use infra-red illumination technology so we can make full use of them, even at night, or when weather conditions are poor.

Operational Partners

We work with over 250 different organisations to help co-ordinate traffic information across the country. Our primary sources of information about incidents are our own Regional Control Centres, our contractors out on the road and the Police. We also have detailed agreements with 116 local authorities to ensure we are aware of any local roadworks that may affect your journey on our roads. We also work with major traffic generators such as ports, airports, entertainment venues, football clubs and shopping centres so that we can give you early warnings of any major events that may delay your journey.

We have a partnership with the Met Office which allows us to plan ahead when bad weather is expected and helps us provide you with travel advice.

The National Traffic Control Centre collects a huge amount of data from the sources detailed above. We have six months’ worth of data available at any time. This amounts to more than two terabytes of data – the equivalent of 2000 copies of the Encyclopaedia Britannica or 32 days of continuous running DVD movies. The next page shows how we disseminate this information to you in the form of useful traffic information.