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Winter and crisis management

A variety of events (snowfall, freezing rain, accidents, incidents, natural or technological disruptions etc.) can severely impact the functioning of transport infrastructure and reduce the mobility of passengers and goods. They can cause crises which endanger users, affect economic activity (by paralysing the transport network etc.) and harm the environment (greenhouse gas emissions etc.).

Faced with such risks, it is important to establish methods, define organisations and develop tools which limit or even negate the impact these events have on the transport infrastructure, thereby ensuring their sustainable use over the long term.

Responding to these incidents and their impact on the transport network involves a large number of stakeholders from a variety of bodies (regional authorities, network mangers, transport operators, the police and departments of the Ministry of Ecology, Energy, Sustainable Development and the Sea (MEEDDM) etc.).

The management of winter weather situations is closely related to crisis management. Indeed, the first may well lead to the second, and both require the coordinated action of the stakeholders involved in operating transport infrastructure.

This issue concerns 3 areas impacted by ITS development:


  • Road network monitoring

Network monitoring

The monitoring of the road networks, in the context of winter and crisis situations, makes it possible to determine and monitor changes in weather conditions as well as the state of the road surface on the road network. In tunnels, sensors are used to monitor air quality. Understanding and controlling these components contributes to determining traffic conditions on the network in poor weather conditions as well as the foreseeable changes in these.

The monitoring of networks aims to provide assistance for network managers in analysing the winter risk and taking the appropriate decisions. This monitoring is implemented by deploying more or less complex systems and technologies on the networks which range from hand-held measuring tools to comprehensive systems which take into account road and weather factors, comprising notably of integrated systems for predicting the state of the road surface.



  •  Events and crisis management

Event response

Different types of events (snow disruption, accidents etc.) impact network operations in different ways. Their impact notably depends on the nature of the event, whether it was forecast or not, the duration and the volume of traffic on the network etc. It is therefore vital that both the event and the environment in which it takes place are correctly characterised.

Event response has been subject to numerous studies to develop and make available to network managers decision support tools or even expert systems adapted to the situations encountered in winter periods or crisis situations. These systems provide strategies to limit or negate the effects of these events on the operation of the network, according to the specific event and the environment affected.

The systems developed provide responses to very different issues and call on diverse technologies depending on the event requiring a response. They notably aim to the need for:

  • Strategies to implement according to the specific event (traffic management plan, response and safety preparedness plans, etc.);
  • Response guidelines to be adapted to the road weather phenomenon concerned (type of road salting, scraping, preventative or responsive actions, dosage, etc.)
  • Improved identification and forecasts of poor road-weather conditions, and corrective action where required;
  • etc.


  • Traffic management during crisis

Traffic management in crisis situations

Traffic management in disrupted situations, requires a specific type of organisation (winter resilience, crisis management control centres, etc. ) and specific operational measures. The latter are intended to inform users about disruptions to the network but also to “manage” traffic flows and, if necessary, the entire road network in order to mitigate or even negate the impact of these disturbances.

The traffic management measures activated should work together to compensate for the disruptions observed; this requires a good understanding of the impact each measure has over time and of their combined effect. Furthermore, the management of HGV in winter crisis situations requires specific measures (HGV stacking etc.) to keep this type of traffic under control. These requirements and constraints mean that traffic management in crisis situation engineering needs to be developed to define the most-effective and best-adapted measures to implement when managing these events. Research work is also being carried out in collaboration with our European partners under the EASYWAY project in order to establish guidelines for these fields.

This traffic management engineering should also take into account the environmental impact of the management of winter situations on transport infrastructure.

Finally, it should also form part of a multimodal and intermodal approach to offer, where possible, appropriate alternatives to road transport.