ENV 12313-4:2000

FOREWORD
INTRODUCTION
1 SCOPE
  1.1 Application
  1.2 Presentation
  1.3 Service management
  1.4 Transmission
2 NORMATIVE REFERENCES
3 APPLICATION
  3.1 Content of the TMC "travel service"
  3.2 TMC terminal
  3.3 Event-orientated information (ALERT C)
  3.4 Status-orientated information (ALERT Plus)
  3.5 Strategic and tactical information
  3.6 Geographic relevance
  3.7 Transmitted message priority
4 PRESENTATION
  4.1 Event-orientated messages
  4.2 Status-orientated messages
      4.2.1 Message format (variant: 4 bits)
      4.2.2 Collection (11 or 12 bits)
      4.2.3 Statuses (20 or 21 bits)
      4.2.4 Coding mechanism
5 SERVICE MANAGEMENT
  5.1 Introduction
      5.1.1 Pure ALERT C service
      5.1.2 Added value services (ALERT C and ALERT Plus)
  5.2 System messages (32 bits)
      5.2.1 Service layer information
      5.2.2 Network layer information
6 TRANSMISSION
  6.1 System messages
      6.1.1 Type 1A groups
      6.1.2 Type 5A groups
      6.1.3 Type 3A groups
      6.1.4 Type 8A groups
  6.2 Immediate repetition
  6.3 Event-orientated messages (ALERT C)
  6.4 Status-orientated messages (ALERT Plus)
  6.5 Summary

1.1 Amplification: The ALERT Plus function is an extension of the ALERT C function. While ALERT C covers event-orientated information to be conveyed by the RDS medium, ALERT Plus deals with status-orientated information to be conveyed by the same medium. The ALERT Plus function informs motorists about the changes affecting the status of traffic at pre-defined locations.