Driving conditions: monitoring and acting in real time

Whatever the event (e.g. works, traffic jams or accidents), the aim is to reduce detection time – and, more particularly, intervention time – so that optimal driving conditions can be restored without delay.

Traffic management involves dealing with a wide range of predictable and unpredictable components such as traffic, weather conditions, accidents and congestion. A high degree of reactivity is required so that the requisite operations can be triggered and motorists informed through the appropriate use of tools such as motorway information panels and the motorway radio station Autoroute INFO (107.7 FM).

1- Collecting traffic data

REGA uses an extensive network of data measurement points combining two main information vectors: automatic surveillance of everything that can be measured physically and manned dynamic surveillance.

Human action round the clock

• The patrols : (the “men in yellow”) patrol the motorway night and day and inform the regional control unit by radio of any events. Additional information may be provided by other staff working on the ground.
• Gendarmerie patrols are in constant contact with the motorway patrols, and trigger emergency action.
• Emergency roadside telephones (orange columns) are located every two kilometres along the motorway, and every kilometre where traffic is heavy. These enable motorists to contact the gendarmerie in the event of an incident, accident or breakdown.

The automatic surveillance system

The automatic surveillance system – which comprises traffic-count loops, weather stations, cameras and automatic incident detectors – uses a fibre optic network installed along the motorway.

• Traffic-count loops, which are located every 20 kilometres or so, automatically calculate traffic density, flow speed and the proportion of heavy goods vehicles. All of this information is used for evaluating travel times.
• Weather stations located along the motorway measure changes in climatic conditions. The alerts sent by these stations to the control units enable preventive action such as salting to be triggered.
• Cameras placed at strategic locations enable surveillance of motorway interchanges and problematic sectors.
• Automatic incident detectors, which are located mainly in tunnels and in zones where traffic is heavy, provide real-time information on slowdowns, traffic jams and incidents.

Outside partners

• The gendarmerie and/or CRS (riot police) motorway units receive all calls from the emergency telephones, and trigger actions by outside players. The gendarmerie units operate in tandem with the district teams.
• The regional road information and coordination centres or CRICRs (Centres Régionaux d’Information et de Coordination Routières) are in contact with the PC central control unit, and provide information concerning general traffic conditions on motorways upstream and downstream and on nearby conventional roads.

2 – Using the information

All of the information provided by observers on the ground (patrols, gendarmes, Company personnel, motorists, etc.) is input in real time by the control-unit operators. Once validated, this information is presented in diagram form to serve as a decision aid. Using a system of symbols and colour codes, each REGA unit provides an ongoing, real-time overview of current events and/or actions. A red “A”, for example, means that there has been an accident, while a red “+” means “access closed”, a yellow “=” means that works are being conducted, and a white “*” indicates winter service (surface treatment). REGA users have access to three successive zoom levels (general network, regional division and 15 km stretch), which enable them to focus more precisely on a given event.

Since the system is interactive, the user need merely click on a symbol to obtain instant details of the situation. When news of an accident is transmitted, the operator has direct access to a data sheet providing the name of the motorway, the direction concerned, the kilometre value, the number of vehicles involved and the lanes neutralised. A historical database containing all of the information collected enables subsequent reconstruction of events and the generation of forecasts and traffic simulations.

3 – Triggering and monitoring actions

Decision-making – which is structured around the central command and control unit at Dijon-Saint-Apollinaire (Côte-d’Or département) and the regional command and control units – involves a three-tier chain of command encompassing the district, regional and central operational levels and comprising the permanent safety team. At each level, decision-makers optimise their actions thanks to the information provided by REGA. Actions are tailored to take account of individual events, from laying cones for a few minutes while an object is removed to closing the motorway for a longer period when hazardous substances have fallen onto the road surface. Traffic-management staff ensure that additional employees are on stand-by at command and control units during “crisis periods”.