Low Level Function
5.13.9 Determine Applicable Road Information

Overview

This Function shall be capable of providing the following facilities:

(1) The ability to provide support for the Driver to determine the applicable road based information that can be displayed in the Host Vehicle.
(2) The ability to include in the information the current legal speed limit and information about junctions that are being approached as the Host Vehicle moves through the road network.
(3) The ability to receive digital map data from the Geographic Information Provider including legal speed limits and road signs, which shall be loaded into the store of Road Information Data.
(4) The ability to use the data from the store together with the current location of the Host Vehicle in the road network to determine the current maximum legal speed for the Host Vehicle and any approaching changes in road geometry and layout for which signs are available.
(5) If available the ability to apply any override of the legal speed limits provided by the Manage Traffic functionality.
(6) The ability to send the legal or overridden speed limits to other functionality for display to the Driver and for use in monitoring the safety behaviour of the Vehicle.

Functional Requirements

(a) continuously monitor for the receipt of the vehicle position for legal speed, legal speed limit and road information data plus inter-urban and urban legal speed limit override data flows
(b) when in (a) any but the vehicle position data flow is received, load their contents into the store of Road Information Data using the load road information data flow
(c) when in (a) the vehicle position for road information data flow is received and it has changed since it was last received, use the read road information data flow to obtain the relevant contents of the store of Road Information Data and determine what the legal speed limit should be plus other road based information that should be displayed to the driver
(d) send the result of (c) to the Display Current Road Information function in the current road information data flow and to the Monitor Vehicle Safety Behaviour function in the legal speed for safety behaviour data flow
(e) also send the current legal speed limit (either from the geographic information or as overridden) from (c) to the Prepare Extended Floating Car Data function in the legal speed for ISA data flow.

Diagrams

The Diagram(s) is (are) the diagram(s) where you can find the function :
  • DFD 5.13 Provide Vehicle Data and ISA
  • Functional Tree of Area 5

    • Parent Higher Level Function

    Input logical dataflows

    Output logical dataflows

    User needs

    Number

    Description

    7.4.1.48
    Hazardous Location Notification - The system shall provide "copies" of the traffic signs that are relevant to the current section of the road (e.g. speed limit, road hazards, junctions) to the driver at all times via an in-vehicle display.
    7.4.1.49
    Hazardous Location Notification - The system shall be able to send to following vehicles "copies" of the traffic signs, or information about the local traffic (e.g. sudden congestion), that it may be useful to receive in advance.
    7.4.2.5
    The system shall provide "copies" of the traffic signs that are relevant to the current section of the road (e.g. speed limit, road hazards, junctions) to the driver at all times via an in-vehicle display.
    7.4.2.6
    The system shall be able to send to following vehicles "copies" of the traffic signs, or information about the local traffic (e.g. sudden congestion), that it may be useful to receive in advance.
    7.4.3.9
    The system shall provide "copies" of the traffic signs that are relevant to the current section of the road (e.g. speed limit, road hazards, junctions) to the driver at all times via an in-vehicle display.
    7.4.4.11
    The system shall be able to compare the reported speed of a vehicle with the current speed limit and send a warning to that vehicle for display to the driver, via an in-vehicle device, that its current speed is greater than the legal speed limit.
    7.4.4.12
    The system shall be able to compare the reported speed of a vehicle with the current legal speed limit and display a warning to the driver, via a road-side device, if its current speed is greater than the legal speed limit.
    7.4.4.13
    The system shall be able to compare the reported speed of a vehicle with the current recommended speed limit and send a warning to that vehicle for display to the driver, via an in-vehicle device, if its current speed is greater than the recommended speed limit.
    7.4.4.16
    The system shall inform the driver, via an in-vehicle display, that there is a modification to the speed limit ahead, and the reason for it.
    7.4.4.17
    The system shall provide "copies" of the traffic signs that are relevant to the current section of the road (e.g. speed limit, road hazards, junctions) to the driver at all times via an in-vehicle display.
    7.4.4.2
    The system shall be able to warn drivers, via an in-vehicle display, of different legal speed limits as a result of particular weather conditions.
    7.4.4.3
    The system shall provide legal speed limits continuously to the driver via an in-vehicle display according to the type of the host vehicle and the lane in which it is travelling (Intelligent Speed Adaptation - ISA).  A suitable message should be provided if the service provision cannot be guaranteed.
    7.4.4.4
    The system shall provide recommended speed limits continuously to the driver via an in-vehicle display according to the type of the host vehicle and the lane in which it is travelling (Intelligent Speed Adaptation - ISA).  A suitable message should be provided if the service provision cannot be guaranteed.
    8.2.5.2
    The system shall be able to receive mandatory speed limits from outside the vehicle (and store them within the vehicle).
    8.2.5.4
    The system shall be able to display continuously to the driver the current mandatory speed limit.