Operating at the interface [road traffic]

In January 1995, a new motorway bridge opened in Belfast. It carries the M3 over the River Lagan and is located on the edge of the city centre. On its approaches there are 8 traffic signalled interchanges linked to the urban road system within a distance of less than 6 kms. There is, therefore, considerable interaction between the flows on the motorway and where it interfaces with the urban network. The new road has an advanced motorway system supplied by Serco Systems, an important feature of which is the high level of integration between it and the upgraded urban traffic control system, supplied by Siemens Traffic Controls. As travel demand and congestion continues to increase, traffic control systems can no longer be neatly developed and labelled urban or motorway. The current and future development of control systems must have open architecture and transmission protocols that permit meaningful communications of data and instructions between systems and between control centres.