3.4 TTIS-03 Speed Limit Information

3.4.1 ITS service at a glance

Service definition

Drivers should always drive at an appropriate and safe speed. Speed Limit Information services are implemented to help ensure that the driver always and everywhere knows what the speed limit in force is. Speed limits can be static or dynamic; both can be included in information services, and can be provided to drivers via road signage, road markings and in-vehicle systems.

Service objective

For the road user effective speed limit information services mean: 

  • they always and everywhere know what the speed limit in force is.  
  • For the road operator effective speed limit information services mean: 
  • collecting and maintaining, accurate and up-to-date speed limit data sets 
  • ensuring data sets are accessible and useable for traffic management services and service providers in accordance with relevant legislation  

By achieving this vision Speed Limit information services can contribute to improved road safety and a reduction in accidents.

Service benefit radar

ITS service key words

  • Speed limit
  • static
  • dynamic

3.4.2 Harmonization requirements and advice Functional requirements and advice Functional architecture

The function of the service is to provide speed limit information to road users either pre-trip, for more accurate trip planning, or on-trip. This may be demand responsive or led by the information providers. In Europe, both public and private information providers are involved in this information provision (see organisational requirements). Hence the decomposition of the whole service into sub-functions is necessary identifying interfaces to be standardised.

Figure 24 shows the typical functional architecture of a “Speed Limit Information service”  and gives a schematic overview of the typical system architecture required for a speed limit information service, covering

  • static speed limit information collection, storage and updating
  • dynamic (variable) speed limit (VSL) data processes
Figure 24: Functional architecture Speed Limit Information value chain Functional requirements and advice

Functional requirements

  • FR1: Source, scope and quality of speed limit information provided by content owners to content providers must both be defined and part of data interface descriptions.
  • FR2: Speed Limit Informationcollected and information provided by content owners to content providers must be based upon both a consistent geographic reference model and a time validity
  • model, which both must be agreed among parties participating in the service and part of data interface descriptions.
  • FR3: If a speed limit information service involves road operators and service providers, information exchange platform systems between road operators and service providers should be implemented to update the databases
  • FR4: The frequency of the updates of the speed limit databases should be agreed (and published) and ensured by parties participating in the service.
  • FR5: A feedback loop between service providers and the road operators should be put in place to ensure correct data provision and integration in the speed limits databases. Interface requirements

Interface requirements:

  • IFR1: If the Speed Limit service implemented provides data listed below at interface 1 (see Figure 24), it must provide coded information on the current speed limit including the following elements:
    • The maximum Speed Limit
    • Location (section) of the Speed Limit
    • Where necessary, the type of vehicle concerned by the Speed Limit
  • IFR2: If interface 2 is implemented, the Speed Limit Information Service must provide at interface 2 (see Figure 24) C-ITS coded information on the current speed limit including the following elements:
    • the setting of a (variable) Speed Limit sign (gantry)
    • the location of the sign (gantry) and the stretch of road to the next sign (gantry)
    • where necessary, the type of vehicle concerned by the Speed Limit (text)
  • IFR3: When relevant, the Speed Limit Information service should collect at interface 3 (see Figure 24) C¬ITS coded information on Probe Vehicle Data (microscopic traffic situation) such as travel speed, direction, current location of a vehicle relevant to this ITS Core service. Organisational Requirements

Static and dynamic speed limits are data types listed in the Annex of the Commission Delegated Regulation (EU) 2015/962 for the provision of EU-wide real-time traffic information services. This instrument seeks to provide appropriate framework conditions enabling the co-operation of road authorities, road operators and any other ITS service providers involved in the traffic information value chain, and to support the interoperability, compatibility, and continuity of real-time traffic information services across Europe. Therefore, road authorities and road operators collecting speed limit data are obliged to provide it in a standardised format, if available, or in any other machinereadable format to a national access point.

Organisational requirements: 

  • OR1: The organisational and operational structure of the service as well as the role of each public organisation/body and its exact responsibility and task in the chain must be compliant with the National Access Points across Europe, within the scope of the implementation of the delegated acts adopted under Directive 2010/40/EU.
  • OR2: All necessary organisational aspects for successful implementation of a “Speed Limit Information Service” must be documented and agreed by all involved parties/partners to establish the cooperation.
  • OR3: All necessary collaboration processes/workflows and interfaces must be described.

Organisational Architecture / BusinessModel

A general overarching description of the key actors, their roles in the value chain and the related conditions for TTI service provision are outlined in Chapter 3.1. More information on new models of cooperation between public and private partners can be found in chapter

Organisational advice:

  • It is advised that the public authority, responsible for speed limit regulations, is involved in organisation of the speed limit information service. 

Obligation for TTIS provision, data used in the TTIS

Organisational advice:

  • As basic safety road data regulated by public authorities, a speed limit information service may be considered as a free of charge service to the user.
  • Concerning dynamic speed limit information – some characteristics related to the speed limit in place as road works or speed control measures for example – can be managed by private companies. This data issued by different sources may be under public and private scope, cooperation between all parties is advised.


Numerous concerns regarding the implementation of speed limit information service involve the issue of enforcement. At this stage legal effects (enforcement) only result from traffic signs and not from their representation on board with information systems (e.g. navigation devices). 

Monitoring and enforceable obligations arise only in connection with the first one (traffic signs). Static signs and variable message signs count to the legal arrangement of speed limits. In addition, the information about the arranged Speed limits may be given via information systems provided in the vehicle, however this information does not supersede or change the traffic law arrangement; the in-vehicle presentation does not relieve the driver of the responsibility to obey the current traffic law arrangement from VMS and static signs.

Organisational advice: 

  • It must be decided whether the further specification shall be limited to on-board information systems. At least, an accurate differentiation between the legal effects of traffic signs and pure information by onboard systems must be made. It is recommended to exclude Speed Limit Information of enforcement reliability without complete quality check of the information provided. Common Look & Feel requirements

Dynamic speed limit signs are language independent represented in a similar format to traditional metal road signs but using light on a dark background. Dynamic speed limit information may be completed by a danger warning sign or information sign representing the reason for the dynamic speed limit i.e. road works, heavy traffic, raining, slippery road, fog or pollution. Complementary signage should be language independent to ensure all drivers understand important safety information.

ECE/TRANS/WP.1/119/Rev.2 VMS signs concerning speed limit information, and complementary signs, are shown in Figure 25.

Figure 25: Signs required for Speed Limit Information (taken from ECE/TRANS/WP.1/119/Rev.2)

Common Look & Feel requirements:

  • CL&FR1: Speed limits must be consistent and there must be no discrepancies between the static and dynamic signage of speed limits. If this cannot be achieved, the speed limit will not be displayed.
  • CL&FR2: Specific complementary signing of speed limit signage should be language independent. Required standards and specifications

Information provision standards:

  • IPS1: If a Speed Limit service is implemented at interface 1, the Speed Limit information (see IFR1) must be profiled based on EN 16157-3:2019 using the DATEX II Recommended Service Profile for Speed Limits.
  • IPS2: If interface 2 is implemented, Speed Limit information (see IFR2) must be profiled in an

IVIM (Infrastructure to Vehicle Information Message) based on ISO 19321 using the C-ROADS C-ITS Message Profiles for the In-Vehicle Signage service, specifically the Traffic Sign use case as defined in the C-ROADS Common C-ITS Service and Use Case Definitions.

  • IPS3: When relevant, the Probe Vehicle Data (microscopic traffic situation) information (see IFR3) should be collected, which is profiled based on ETSI EN 302 637-2 using the CAR2CAR Communication Consortium Basic System Profile. Level of Service Definition Level of Service Criteria

Table 19 gives the Level of Service recommendations for a Speed Limit Information service. The background of this concept is descripted in chapter 2.6.

Table 19: Level of Service recommendations for Speed Limit Information Level of Service Criteria related to Operating Environment

Level of service requirement:

  • LoSR1: In case that pre-deployment surveys/evaluations provide the necessary evidence to proceed with the deployment of the “Speed limit Information service”, the minimum and optimum LoS should respect the following Level of Service to Operating Environment mapping table.

Table 20: Level of Service to Operating Environment mapping table (see also chapter  2.5.3 and ANNEX C)