ITS technologies perform a key function in gathering prevailing road network information and providing support for other network operation activities. The basis of ITS-based network monitoring is traffic monitoring and detection (such as vehicle detection devices, probe vehicles, sensors and CCTV cameras) and the interpretation and presentation of information on the state of the road network.
A prerequisite for many ITS services, including traffic and incident management is the collection of timely, accurate and reliable information about traffic flow and road conditions. (See Operational Activities) These ITS services can be thought of as part of an information chain that includes:
Network monitoring systems and ITS technologies play a central role in assessing transport network performance in real-time, predicting the most likely state of the network, validating capacity enhancements and supporting long-term planning. The primary applications that enable road network monitoring are:
Operationally the primary organisational structures and functions – necessary to provide a road network monitoring service – may include:
One of one of the most common road network monitoring technologies is CCTV which has been developed to support Traffic and Control Centre (TCC) operations (also known as Traffic Management Centres - TMC). There is a range of other complementary and additional sources such as fixed detectors and the data collected from mobile devices. (See ITS Technologies) The use of vehicles as measurement ‘probes’ is growing, in addition to traditional use of static roadside detectors. (See Probe Vehicle Measurements and Roadway Sensor) Together, these sources can provide reliable, cost effective and accurate journey-time information for the whole road network.
It is always necessary to be confident that the data is accurate and reliable. For example, a realistic representation of traffic conditions needs to take account of fundamental differences between detector types and other sources - that influence how data from each type of detector should be interpreted. To build a complete picture it is likely that data from different types of detectors will need to be combined before it can be interpreted to provide usable information on network status, a process known as ‘data aggregation and fusion’. Such information is basic to the operations of a Traffic Control Centre (TCC), and is often needed in real-time, especially for a complex or congested road network. (See Operational Activities) None of this would be possible without a variety of communication technologies and technical standards to ensure the timely use of traffic data. (See ITS Standards)