Considering that most serious incidents on our roads happen in built-up areas, a fast and effective response is crucial to prevent frustrating jams or, at worse, gridlock. Automatic Number Plate Recognition (ANPR) technology from Siemens Traffic Controls is one of the latest solutions to help with incident management as well as providing information for a wide range of applications.

Local authorities are always under pressure to ensure efficient management and control of the highway network and the traffic management act places yet more demands on them. To meet these, a growing number of local authorities are choosing ANPR technology with very positive results, as the case studies of Devon and Southampton show. They welcome this technology because it reduces the workload of the operator in the traffic control centre, freeing them up to manage the network and improve the service provided to the travelling public.

Accurate journey time monitoring
As well as incident management, one of the biggest advantages of ANPR technology to the operator is the calculation and display of real-time journey time information. This is invaluable in a modern traffic control centre to ensure that the network is operating as smoothly and efficiently as possible. Traditionally, this was implemented using the resources of an Urban Traffic Control system and in some cases the data available from SCOOT. However the nature of detection available through a UTC system means that any calculation of journey time is always based upon estimates and observations of traffic behaviour which may have been carried out some time ago. The use of Automatic Number Plate Recognition technology, linked to a modern traffic management and control system, allows live journey time information to be displayed, not only to the operator in the control room but also to the public, either before they travel or during their journey.

By directly monitoring the flow of individual vehicles through the road network, ANPR provides a new and very accurate measure of the current journey time between many different measurement nodes. This information can prove vital in the selection of strategic control measures to ensure the network is operating as efficiently as possible.

By combining information from different ANPR links into a single route, operators in the control room can very easily obtain the overall picture of what the current situation is and respond accordingly. The implementation of ANPR for journey time monitoring has been widely trialled in a number of key schemes, the largest of which was the introduction of congestion charging in central London.

Devon County Council
Devon County Council is one authority keen to see the advantages of ANPR in monitoring journey time information and overall network performance more accurately. With 39 cameras capable of reading number plates and 19 colour overview cameras planned for key radial routes into Exeter city and on the A380 at Newton Abbot, with more to follow, ANPR is set to give the county’s ongoing congestion management strategy a real boost.

According to Peter Hookham, the Council's Intelligent Transport Systems Engineer, the use of this technology is embedded in the County's Strategy for ITS. Peter said "This technology will allow us to better inform travellers about the strategic routes into the City and major towns. It will give us the opportunity to create a road timetable so that journey times between fixed points on the network are known. This information will be available via the Council website and through traffic information broadcasts so that travellers will be able to access it both pre-journey, where they have the option to modify their time or mode of travel, and in-journey where they can make decisions on route choice based on real time travel data."

Continual origin and destination modelling
The number plate data generated by the cameras can be used to provide a continual review of traffic flows on all major routes within the urban area. It can also provide a continually updated “on-line” origin-destination matrix for use in conjunction with micro-simulation to develop new traffic management schemes in the most cost-effective and environmentally appropriate manner. Future applications could also include on-line modelling of incident responses, in real-time, to determine the best course of action as an incident unfolds – further improving operator efficiency.

Future-proof communications
Given the continual evolution of communications technology, the initial installation may be different to any future expansion and it is imperative that system architecture copes with this to minimise any revenue exposure to the operator. Modern ANPR systems must be able to support a wide variety of different communications methods to provide this flexibility and security for the future. Options which should be considered are GPRS, DSL and Ethernet to be combined on a single ANPR system to ensure the most appropriate communications solution is available for each outstation installation.

The ongoing development and installation on street of UTMC also provides benefits, in terms of instation integration and also the implementation of modern communications link with on-street devices. This provides the potential for revenue savings by sharing these communications links for nearby ANPR camera installations.

Insightful integration
The operator in a modern traffic control centre must manage information on the current status of the road network from a variety of disparate sources, including ANPR. The accurate journey time information provided by ANPR is only of use to the operator when considered as part of the overall “bigger picture”. In order to realistically achieve this, the data from the ANPR cameras must be integrated into an overall UTMC traffic management system, such as COMET.

This then allows the operator to analyse the “bigger picture” and implement a coordinated, strategic response across the range of systems available, to control the resulting traffic flows and provide information to travellers, both before and during their journeys.

Getting the message across
The use of a UTMC common database such as COMET has greatly simplified the process of information dissemination. Now, a wide range of disparate traffic and travel related information is available from one common source within the traffic control centre. This has improved the information relayed to drivers in a number of ways.

Existing hardware on the street, such as VMS, allows information to be communicated directly to the driver from the traffic control centre, along with radio broadcasts and the potential ability in some vehicles to use RDS-TMC to provide the information.

For local radio stations, the use of the UTMC common database approach has made collating salient traffic information much simpler, with everything now presented within one, easy to use operator interface. The information included on the database from the ANPR camera network provides an immediate indicator to the broadcaster of the current state of the road network, regardless of whether CCTV coverage is available on the routes into or out of the town.

This technology also means more comprehensive traffic and travel websites are now available to motorists. The information will enable them to make decisions about when to travel and which route to take, bypassing any hold-ups.

With all of the data required for the website stored centrally as part of the UTMC common database, the process of updating the website is automatic, again reducing operator workload, and allowing them to concentrate upon the management of incidents.

Southampton City Council is confident ANPR technology will bring a improvement to traffic flow within the urban area. Ray Morris, Traffic Systems Manager for Southampton City Council says: “ANPR will enable us to provide even more accurate information on the major routes and will allow the traffic control centre to manage the network more efficiently. In addition it will provide the City Council with reliable comparative information on the performance of the network.”