Birmingham Digital Ring

As England’s second city, Birmingham is heavily reliant on the efficient flow of its traffic network. This is particularly acute for Birmingham as it lies in the heart of the heavily built up and densely populated West Midlands and is encircled by three motorways. Known as ‘The Birmingham Box’, the M5, M6 and M42 carry over half a million vehicles every day and any problem can rapidly escalate into a major traffic nightmare.

Monitoring and managing this motorway network is the Highways Agency (HA), who rely on a network of cameras to see where traffic is building up, where accidents have occurred and where diversionary action needs to be taken. With such high dependency on the Birmingham Box, the HA could not afford downtime or inefficient operating systems and, therefore, embarked on a £1.9m overhaul of their surveillance network. AMG was chosen to develop a new network that would cope with traffic flows now and in the future - the Birmingham Digital Ring.

AMG installed the AMG2800 multi-channel video transmission system to link four motorway transmission stations at Ray Hall, Bromsgrove, Umberslade and Coleshill with the Police Control Office (PCO) at Perry Barr and form the Digital Ring. Using an existing dual fibre optic ring, capable of transmitting live, full bandwidth video images from 160 of the hundreds of cameras positioned anywhere on the network. The uncompressed video allows the PCO and the Highways Agency’s Regional Traffic Control Centre high quality, real time monitoring of traffic flow around the entire West Midlands region. Critically, in the event of a break or catastrophic damage to one of the fibre optic cables, the AMG equipment allows the video and data on the network to be automatically re-routed, maintaining system integrity round the clock.

As well as the currently provisioned 80 uncompressed video circuits, the AMG system also carries 40 data and audio circuits together with 10 Ethernet circuits to give the HA fast and comprehensive coverage, 24 hours a day, 7 days a week.

“This highly developed system gives us an exceptional resource in our traffic management strategy”, comments Ian Harrison, Senior Traffic Technology Engineer for the Highways Agency. “Enabling the PCO unrestricted access to live video streams from any of the more than 280 cameras gives a level of flexibility, insight and control that is crucial for traffic management around a major city like Birmingham. Our investment in one of the best surveillance and management systems possible will also benefit motorists”.

The transmission stations at Coleshill and Ray Hall are each equipped with an engineer’s position to allow maintenance functions to be carried out.

Each is equipped with a control panel and a video monitor to which any camera can be routed to make fault finding quicker and easier. The data circuits are used for a number of purposes including the control of the fibre chassis themselves, matrix control, wind speed data collection, control panel highways (for the engineer’s positions), V26 audio (camera control) and cross boundary data (TV Network Protocol).

Working through Tyco Integrated Systems (TIS), each motorway camera site was connected to the nearest transmission station on the digital ring. The cameras are presented to a video matrix and a battery of digital video recorders (DVRs) record and archive all of the feeds. This material may be retrieved and viewed by any control room operator at any control room over the system’s Ethernet channels. It is also used by the HA’s new Intelligence Unit to monitor and record traffic levels and analyse traffic patterns for future traffic planning.

Each of the transmission stations can also exchange video and data with surrounding video surveillance networks. In this way, the impact of traffic incidents both on the Birmingham Box and the surrounding road network can be assessed. It would also be possible to incorporate information from these feeder routes into the Perry Barr PCO in future.

The flexibility of the AMG system allows foreseeable future upgrades to be accommodated easily by re-configuration of the system, without significant disruption. The capacity of the system can be increased by 100% without any disruption to the current network. Movement of the main control room or the creation of secondary control rooms can be done with ease.

Linking in other parts of the national network or both incoming and outgoing signals allows for a nationwide management system. The flexibility of the system was demonstrated subsequently to the main installation by the move of the main PCO at Perry Bar to a totally new node on the ring at Quinton.

“Using the fibre optic system we have been able to double the amount of CCTV motorway monitoring in the West Midlands without the need to install additional cabling. This has reduced the amount of equipment required and improved how we manage traffic if the motorway is closed or if an incident occurs. “The resilient, self healing capabilities built in to the system are particularly relevant to round the clock surveillance operations in all spheres, not just road management. By choosing the AMG2800 series we did not have to sacrifice video quality. Unlike other video solutions, running on SDH or IP Networks, AMG2800 does not compress the video signal making high quality, real time video to every monitoring screen a reality”. Ian Harrison

• Each of the 280 cameras is linked to one of four transmission stations or the Police Control Office (PCO).
• Each transmission station on the ring is linked to the PCO.
• The digital backbone comprises eight AMG2800 transmission hubs equipped with video and data cards. Four hubs transmit on different wavelengths in the clockwise direction and four transmit on different wavelengths in the anticlockwise direction.
• The bi-directional channels provide resilient redundancy in case of fibre breakage. If a fibre or cable is unavailable, the system automatically switches video signals to the other direction and a fault reporting system advises the maintenance engineer of the problem.
• Digital video recording is provided for each camera and 10 Ethernet channels provide a fast reliable communications medium for retrieving DVR data.
• 40 data circuits carry other information, such as the control of the fibre chassis themselves, matrix control, wind speed data, control panel highways (for the engineer’s positions), V26 audio (camera control) and cross boundary data (TV Network Protocol).
• Each transmission station has matrices to switch cameras onto the digital ring, pictures to the engineer’s positions or cross boundary connections.
• Two transmission stations are equipped with an engineer’s position to allow maintenance to take place.
• A Video Routing Manager at the PCO controls both the video matrices and digital transmission backbone.