Urban-ITS Traffic Management Data Models

 

Introduction 

Standards supporting the exchange of traffic management information have existed for some time. The CEN 16157 DATEX II family of standards have been used widely across Europe in an inter-urban and strategic road network environment.

There are a variety of means to manage the road network and address traffic congestion and traffic disruption (e.g. planned/unplanned events, accidents, floods, fires, etc.) through traffic management in an efficient and innovative manner. For instance, a number of cities put in place different types of traffic re-routing, traffic prioritisation and access regulation measures, including intersection management, targeting all or a subset of vehicles (e.g. deviations, priority lanes, green waves, road user charging or tolling, low emission zones, low speed zones and pedestrian zones). Unfortunately, these measures are not necessarily managed in a holistic and coordinated manner and often not correctly taken into account in the outputs from traffic information systems towards users (e.g. navigation devices). Therefore, establishing on one side coherent specifications, compatible standards and practical interfaces supporting the interoperability of data necessary for up-to-date traffic information, and optimising on another side a variety of traffic management and prioritisation measures, rightly supplemented by standardised technological solutions for vehicle identification (i.e. as regards vehicle categorisation, emission class, character of emergency, load factor), would both contribute to the overall efficiency of traffic information and management in urban areas, including access regulation management and enforcement.

Compatible data formats, open and documented interfaces and protocols for transmission of relevant data, independently of their source (e.g. sensors, floating car data and traffic control centres), and their integration in current and future traffic information systems and traffic management operations, for various road networks including urban-interurban links need to be developed (i.e. worked out where necessary).

Objective

One of the main findings from the Prestudy Urban ITS is that there are a number of major gaps that will weaken the ability of Urban Administrations to implement urban ITS efficiently, and in some aspects, gaps may prevent its introduction unless faced and provided as a matter of urgency. There are, additionally, a number of highly desirable aspects that could much better assist Urban Administrations to implement Urban-ITS.

The objective of this study is to identify the standards and actions necessary to enable urban infrastructure coordination to support the deployment of Urban-ITS. In particular, the study will concentrate on what is relevant to the Urban ITS prestudy High Level Recommendation HLRj: Intelligent transport systems Traffic Management –– Data Models and interfaces:

  • extending the existing DATEX II data model defined in the CEN 16157 family of standards to better address concepts occurring in the urban environment;
  • to provide specification for the publication of Traffic Management Plans extending the existing DATEX II core model to better support application to the urban environment.
  • addresses the publication of traffic signal related information that are most relevant in the urban environment, covering the exchange of static information related to the intersections and road segments belonging to a road network, related to traffic signal-controlled intersections and dynamic information related to traffic signal-controlled intersections belonging to a road network. Both of which support the linkage of C-ITS connected vehicle concepts to traffic management data exchange.

Scope

The scope of the project is to produce a standard on Intelligent transport systems – Traffic Management Systems – TM Data Models
defined as follows:


a) A coherent data model covering urban traffic control & management, such as traffic volume, occupancy rates, average speed travel times, traffic condition (Level of Service - LoS), events & incidents and circulation and traffic management plans (TMPs).

b) A geographical (route and intersection) and topological data model for road networks, based on the requirements of known applications (i.e. SPaT/MAP) and the standards already in use by digital map applications. It should be noted that this scope is geared to complementing DATEX II as a centre-to-centre standard.
Following considered discussions with the DATEX II Steering Group, DATEX II Technical Management Group and CEN/TC 278/WG 8 who lead standardisation of the Parts of the CEN 16157 DATEX II family of standards, it was agreed that two Technical Specifications, covering the scope above, would be prepared. 

  • Intelligent transport systems - DATEX II data exchange specifications for traffic management and information - Part 8: Traffic management publications and extensions dedicated to the urban environment
  • Intelligent transport systems - DATEX II data exchange specifications for traffic management and information - Part 9: Traffic signal management publications dedicated to the urban environment