Road network monitoring is a strategic function that enables effective road network operations and incident management. The purpose of network monitoring is to secure accurate, reliable and up-to-date information about road and traffic conditions across the network. A number of activities are required to achieve this:
Traditionally, roads and highways were owned and managed by public bodies as an asset. In the past these bodies were responsible for deploying traffic detectors, filtering and combining their outputs, making them available for traffic management purposes and for displaying messages on Variable Message Signs (VMS). Many road authorities still do this, but in recent years several trends have contributed toward new organisational structures for network monitoring, including:
Private sector service providers have a growing role. Innovations in mobile social networks and mobile phone-based navigation services mean that the users of traffic information may also act as a source of traffic data, otherwise known as ‘crowd-sourced’ data. (See Data and Communications) In future, this may complement conventional point-based vehicle detectors in regions that cross-administrative boundaries, on roads where detectors do not exist, or even on roads where detectors do exist. These new data services (See Future Trends) can assist and complement public highway agencies.
The ITS architecture for the information chain comprises three parts:
Sub-function 1 – the devices and applications for the collection of traffic data (in addition to weather and journey-time monitoring) from:
Sub-function 2 – the processing that combines real time data with any traffic prediction and journey time information that may be derived from the sensor data collected. (See Data Aggregation and Analysis)
Sub-function 3 – the selection, organisation and presentation of information (derived from sub-functions 1 and 2) to the Traffic Control Centre (TCC) operator.
The main application area for network monitoring are: