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.
For the road user effective speed limit information services mean:
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
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 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 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 184.108.40.206
Obligation for TTIS provision, data used in the TTIS
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.
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.
Common Look & Feel requirements:
Information provision standards:
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.
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.
Level of service requirement:
Table 20: Level of Service to Operating Environment mapping table (see also chapter 2.5.3 and ANNEX C)