The scheme was devised installed and operated by Serco for the construction project, which was undertaken by Coastain Ltd on behlf of the Highways Agency. The A282 is the M25 south of Dartford crossing.
The CCTV system installed is an aid to locating and dealing with breakdowns, accidents and other incidents on a section of the road where a long-term contraflow is in operation during major road improvement works to ease traffic flow in the vicinity of the Dartford Crossing over the River Thames.
The installation incorporates 30 cameras to observe the traffic flow on the road, all of which are PTZ domes from the Siemens range.
Zoom rangers
“In the past, we wouldn’t have been able to use dome cameras,” said Ian Kendal of Serco, “because we simply wouldn’t have been able to get the zoom range we need with the lenses they could accommodate. Now, however, the latest Solaris dome cameras from Siemens can be fitted with 24:1 zooms. This gives us everything we need, and allows us to take advantage of the lower cost, easier installation and robust construction of the dome cameras.”
The cameras in use on the A282 installation all feature digital interfaces and are linked with the project’s control room via single-mode optical fibre connections.
The control room, where the images from the cameras are monitored, is equipped with 12 viewing screens. Two 32-inch screens show the main views selected by the operators, while 10 smaller screens are available to display pictures of the area around an incident, or for general monitoring over the whole of the area covered by the CCTV installation. Two operators are on-site twenty-four hours a day, seven days a week.
Pictures from the cameras are stored on an Eventys Lite digital video recorder, also supplied by Siemens, which records on hard disk drives similar to those used in computer systems. In this project, the recordings are stored for a minimum of 60 days.
They have proved to be of great value not only in evaluating incidents, but also in determining whether insurance claims made by motorists passing through the monitored area are valid.
Caption recognition
Since the installation involves a large number of cameras, all of which can pan, tilt and zoom, the operators cannot always immediately recognise the area covered in a live image or in a recording. In order to address this issue, Siemens has incorporated a captioning system for the images, which superimposes text detailing the exact camera location and its direction of view.
“The system was easy to install and set up,” said Ian Kendal, “and it has performed faultlessly. It enables us to direct breakdown trucks and other emergency assistance to hundreds of motorists and lorry drivers, and it is an essential tool in helping us to deal efficiently with more serious incidents.
“Compared with the costs associated with the traffic congestion that would inevitably have resulted had we not installed the CCTV system, it has recovered its installation and operational costs many times over.”
When the section of the Dartford area road improvement scheme has been completed the Serco CCTV installation will no longer be needed and the equipment will, therefore, be removed and re-deployed at another site.
