The core data used to assess and manage the roadway is collected and collated by manual methods and automatically for use in both real time and non-real time applications. Choice of equipment and methods is dictated by the required services as well as the available human and financial resources. (See Methods & Procedures and Vehicles & Roadways)
Example data includes:
Care must be taken not to overload operators and systems with data and information without sufficient filtering or analysis. The following questions must always be addressed:
Certain constraints must be considered. The organisation will need to
ITS-related monitoring systems are characterised by the use of electronic sensors, data processing by a central computer, and data transmission. The system requirements are heavily dependent on the operational activities that it will support (operating, controlling and providing services) and the road network characteristics under consideration. (See Information & Data Gathering)
When an existing (legacy) system needs to be incorporated in the new monitoring system, it is important to evaluate the system applicability for continued use and whether it can satisfactorily accommodate new requirements.
Privacy is a critical issue when incorporating detection technologies that can identify individual vehicles. Typical technologies for these include CCTV, video image processing, automatic vehicle identification (AVI) and cell-phone tracking. It is therefore important to agree a policy of how to respect privacy at all stages: when information is collected, when it is being used and when it is exchanged and transmitted between relevant organisations, including making it available to the public. (See Privacy)
Automated incident detection is most commonly found in urban areas where traffic congestion during peak hour periods is experienced. However, initiatives such as e-Call (Europe) are developing integrated emergency response infrastructure, which will improve detection and response to incidents in all areas (rural and urban) by means of global positioning, in-vehicle sensors and satellite and cell phone technology. In-vehicle systems where on-board electronics improve the driver’s competence in congested travel conditions, at night or in bad weather, can also reduce the occurrence of incidents. (See Automatic Incident Detection)
In the case of automatic detection, the reliability of the monitoring system needs to be evaluated after installation, with respect to the detection function, the telecommunications function, the data processing function and the overall system function. Typical evaluation points include accuracy of measurement, timeliness of data transmission and processing, ability to provide required data, reliability of software algorithms, system resilience under required environmental conditions and maintenance costs.
In the case of non-automatic detection such as phone calls from users, the reliability and accuracy of the data also becomes an important issue. Another issue is the problem of operators receiving too many calls with redundant information. This often happens in the case of large accidents that many people can clearly observe.
Information from road users can be gathered directly by the traffic or operations centre or through a dedicated call centre. In both cases it is very important to handle the gathered information quickly and to confirm its value through the use of the other information sources (such as loops, cameras, mobile patrols). Information from drivers can also be a complementary input for the traffic centre database and is an important tool where monitoring equipment is limited.
User feedback concerning the efficiency of the roadway and traffic conditions is a useful input for determining the perception of the network monitoring operation. This can be achieved through:
Detection systems can enable information to be given to the network operator regarding the onset (or probability of onset) of difficult weather conditions (fog, black ice, snowfall, cyclones, dust-storms) or other unfavourable natural events (landslides, floods). The network operator's task is to respond by issuing appropriate advice on road use through all available channels. (See Traveller Services)
This requires systems for the collection, processing and centralisation of counts and information, organised relations with the safety and emergency call-out services or the assistance services, automatic or non-automatic warning systems (emergency call network, automatic incident detection), and the organisation of regular patrols on the most sensitive roads. (See Data Aggregation and Analysis)
Real-time data accumulation to serve as historical data is an important task of the monitoring mission. It can be used in such a way as to compare real-time data with historical data and find out the presence of incidents on the network. Before/after study of operations and control functions also depends on comparison of these data. In addition, historical data can provide important information to the ITS-unrelated programs of network improvement such as geometric improvement and pavement rehabilitation. (See Data Management and Archiving and Data Ownership and Sharing)