Multimodal Traffic Management Concept Model 

Multimodal Traffic Management (MTM) is a new concept. To provide an overall understanding of what MTM is about, an MTM concept model is established to define the overall MTM concepts. This is more than a list of definitions. It is a model where the relations between the concepts are defined to facilitate a deeper understanding.  

The model addresses aspects of MTM, such as the transport network in which the traffic is managed, the zones of the network in which regulations and measures are applied, and the traffic orchestration strategies used.  

The MTM Concept Model is presented in the intermediate version of the Polycentric Multimodal Architecture, ORCHESTRA Deliverable D3.2

The final version is planned for January 2024 (Deliverable D3.3). 

The MTM concept model is multimodal. This means that the terminology used is mode-agnostic and may deviate from the terminology used in individual modes. The model does, however, as far as we know, comply with plans for future traffic management within all modes, and the multimodality arranges for common references and a common understanding that is crucial when silos are to be bridged. 

Different concept categories are used: 

• Stakeholder (yellow): These concepts refer to generic stakeholder roles. 
• Spatial (grey): These concepts are spatial objects (points, boarders, areas, airspace, etc.) representing smaller or larger parts of the transport network or locations in the network infrastructure.  
• Context (light blue): These concepts constitute a context or premises for traffic orchestration. 

• Measure (pink): These concepts represent measures taken in traffic orchestration. 
• Rules (beige): These concepts represent concrete rules for traffic orchestration. 
• Orchestration (blue): These concepts represent resilient traffic orchestration within a governance area, and cover anticipatory management, stochastic planning, deviation handling and efficient recovery back to normal situations. 

Transport Network concepts 

An MTM ecosystem may consist of several transport networks. A Transport Network has a Mode (road, sea, rail or air), but there may be several Transport Networks per Mode.  A Transport Network is operated under one or more Legislations (e.g. national and European) that may be adapted to International Agreements (e.g. those that apply for air or sea transport). A Transport Network may be connected with other Transport Networks.  

A Transport Network is composed of Network Segments, which are a smaller or larger part of a transport network (e.g. a road, a certain distance along a road, the roads within an area, a part of a fairway, railway segments, or a part of the air space). Several Network Users may use a Network Segment (e.g. pedestrians, cyclists, cars, busses, trains, vessels or planes). 

A Transport Network may have several Zones. A Zone may include one or more Network Segments, and it has a Traffic Orchestration Policy, which a Strategic Planning Manager defines. Such a policy defines the overall traffic management objectives and strategies regarding the traffic management in the Zone, e.g. permanent measures like road pricing measures and rules for priorities. 

A Zone may have Regulations, which must be aligned with the Legislation and adapted to the Traffic Orchestration Policy. Regulations may be dynamically adapted to the situation. Roads may, for example, have speed limits or other constraints adapted to the traffic and weather conditions. 

Overall Transport Orchestration concepts 

Usually, a Traffic Orchestrator does Traffic Orchestration in one Governance Area (GA). However, in some cases (e.g. if there are technical problems in one area), the Traffic Orchestration may cover several GAs. The spatial extension of a GA is defined by the Strategic Planning Manager. It depends on strategic or mode-specific decisions with respect to how GAs should be organised, the complexity of the traffic in the area in need for monitoring and control, and also practical constraints. Thus, GAs may vary in size and be structured as non-overlapping areas or in a hierarchy.  

A GA is a specialisation of a Zone and inherits the properties of the Zone (see above). Thus, a Transport Network may have several GAs, but a GA is related to a single Transport Network and, thus, also to a single Mode. A GA has a Traffic Orchestration Policy and Regulations that outlines the overall policy, strategy and regulations for the whole GA. 

The Traffic Orchestration monitors Transport Operations requested by the Transport Service Providers, managed (planned and controlled) by the Fleet Operators and executed by Network Users. The Traffic Orchestration also monitors and manages Transport Network Conditions and Capacities and occurred or potential Traffic Situations and Events. 

To handle the traffic, permanent and dynamic  Zones with Regulations are defined and managed, and measures are taken within Zones to implement the Regulations. The Transport Operations and the Network Users may have Certificates that confirm properties and abilities, e.g. the type of operation, the greenness of the Network User, the right to access an area, etc. Such Certificates may guide traffic orchestration decisions. Certain types of Network Users/Transport Operations may for example, get privileges.  

The Traffic Orchestration will also coordinate with the Traffic Orchestration in neighbouring GAs, networks and modes. Congestions in one GA may, for example, affect the traffic flow in adjacent GAs. 

Transport Demand Management concepts 

Transport Demand Management is a specialisation of Traffic Orchestration and inherits the properties of Traffic Orchestration. The measures are taken according to predefined conditions, and there may be different types of measures, e.g.: 

• Information Measures: They provide information services, targeting Transport Service Providers, Fleet Operators, and/or Network Users to influence both planned and ongoing Transport Operations and may, for example, motivate Transport Service Providers and Fleet Operators to use other modes or networks, to use other routes, or to change their plans and time schedules. They may also communicate information on regulations and traffic situations, affecting the transport network’s use. 

• Monetary Measures facilitate payment transactions related to the Network Users‘ operations in Zones. 
• Traffic Calming Measures target Network Users and aims to reduce traffic. Speed limits may, for example, be reduced, or the number of Network Users within the Zone may be managed. 
• Access Control Measures control the Network Users’ access to a Zone. The access might, for example, be linked to certain Certificates. 
• Priority Measures assigns priorities to Network Users regarding using the Transport Network Segments in Zones. Priorities might, for example, be linked to certain Certificates.  

Demand Capacity Balancing concepts 

Demand Capacity Balancing (DCB) is a specialisation of Traffic Orchestration and inherits the properties of Traffic Orchestration. DCB is about the handling of an imbalance or a potential or foreseen imbalance between the traffic volume and the transport network capacity. Depending on what is possible, and the aim is to avoid unwanted situations, to reduce the extent of unwanted situations, to limit the negative effects, and to re-establish the normal situation as efficiently as possible after an unwanted situation.  

An Operation Plan supports the DCB. It provides an overview of upcoming events and situations (arrivals, departures, weather conditions, etc.) as well as the Measures to be taken and when they should be taken. Arbitration Models guide the handling of conflicts and trade-offs between different needs. The relevant Measures are: 

• Dynamic use of Transport Demand Management to balance the traffic volumes with the network capacity. Access control may, for example, be used to reduce the traffic on the road with an ongoing emergency response. 
• Individual Measures towards individual Network Users. They are controlled or guided to contribute to an improvement of the situation. 

• Capacity Adaption Measures to adapt the network capacity through the use of relevant mechanisms (speed regulation, new use of lanes, etc.). 
• Coordination Measures to coordinate the distribution of traffic with the Traffic Orchestration in neighbouring networks and modes.