Road Network Operations
& Intelligent Transport Systems
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Other Monitoring Sources

Static detectors and probe vehicle measurement provide complementary views of the performance of the road network through roadside observation and by passively monitoring individual vehicles. These techniques are adequate, most of the time, for managing traffic operations. AID can improve their effectiveness in responding to accidents and planned events. Other sources of data that can help better manage a road network include:

  • ad-hoc reports from the police, emergency services and public transport operators using voice, fax or other data interfaces
  • traffic information provided by privately operated fleet management and navigation service providers such as TomTom based on probe vehicle measurement (South Africa)
  • congestion alerts provided by crowd-sourced information providers such as Google and Waze

During an incident, the mix of traffic data available to road operators is likely to change, with increasing amounts of information arriving from both reliable known sources (“trusted”) and unproven (“untrusted”) sources. Some of the information received may conflict with current knowledge - potentially highlighting a change in circumstances or new and unrelated incidents. The effective use and management of all data sources is critical to effective network operations, particularly during the incident management process.

A well-designed cost-effective traffic management operation needs to recognise the existence of other data sources and to provide the means to include them in its traffic and incident management strategy. Data sources and data owners, other than the highway authority or road operator include:

  • the data source (such as the police, public transport operator, or social messaging services monitor)
  • the type of data provided (such as planned tunnel lane closure, bridge closure;
  • the process by which the data is provided including the interfaces (voice, file transfer, Internet Protocol (IP) or a proprietary data format)
  • and the standards, rules or agreements that might apply to the collection and use of the source of data

The figure below shows the role of other parties alongside road operators in the traffic data collection process. By way of illustration:

  • weather stations may not be owned by the road operator but the data could be provided to them through a partner data sharing agreement with the source owner - perhaps another public authority, a university or third party
  • ad-hoc information such as voice reports from the scene of an incident need to be recorded in a standardised, auditable format that can be retransmitted to other parties involved in managing an incident (this improves the handling of the incident and can be used to inform any review of the incident management process)

Whatever the source of the data, it needs to be assigned a level of trust by the road operator to help it prioritise sources and ensure that the reliance placed on a specific source is appropriate. Data sharing agreements between organisations should clearly specify each parties’ respective roles and responsibilities – and be formally documented (perhaps in a Memorandum of Understanding) and agreed by all parties. The road operator will also need to develop a policy and procedure for handling reports by the public – and to record this for its staff in an operations handbook.

Organisational Model and the relationship with other parties. Reproduced by permission of the EasyWay Consortium ( a trans-European project co-financed by the European Commission.


The variety of other data sources available is matched by the variety of data formats and the trust that may be placed on the sources. The most cost-effective data sources for developed and developing countries are existing sources – but it is important to check that they are reliable and suitable if they were designed for another purpose (such as a weigh-in-motion sensor). A rigid definition of sources may not be relevant – and a traffic operator will need to apply discretion and judgment to the value of the reports received from them. Whatever the source, all data collected needs to include as a minimum - location information and a time stamp.

Where additional information is needed to improve traffic operations or incident management, site observers may be deployed to specific locations to collect survey data, report on traffic behaviour at planned events or to provide real-time information by voice (mobile phone or private mobile radio) or handheld computer at the location of an incident.

Data Exchange

Standardisation of data formats, protocols and communications interfaces is desirable to avoid misunderstandings or conflicts between organisations – such as the data provider (a Police Incident Control Centre) and the data receiver (the Traffic Control Centre – TCC).

If a data interface is required, a technical interface standard can help ensure that a TCC can add new sources easily - whether the data is provided from another system (Centre to Centre, C2C) or directly from a device located in the field (Centre to Field, C2F). Examples include:

  • the DATEX II specification for interoperable machine-to-machine communication of ITS services (Europe)
  • NTCIP Specifications (US, Hong Kong and elsewhere) that include reference to the Common Object Request Broker Architecture (CORBA)
  • the JT/T and GB/T series of standards issued by the Transport Department of China


Reference sources

US Department of Transportation. National Transportation Communications for ITS protocol (

Object Management Group (OMG) Common Object Request Broker Architecture (CORBA) (

DATEX: a standard developed for information exchange between traffic management centres, traffic information centres and service providers

EasyWay Consortium (2012) Traffic Condition and Travel Time Information ITS Deployment Guideline, TIS-DG03-05 pp18-19,