Low Level Function
3.1.2.14.2 Output c&i to Drivers using Inter-urban Roads

Overview

This Function shall be capable of providing the following facilities:

(1) The ability to output information, and/or warnings, and/or commands to Drivers using the inter-urban road network by mechanisms other than In-vehicle displays.
(2) At the same time, the ability to forward the information, and/or warnings, and/or commands to be sent to other functionality for subsequent output to approaching Vehicles and for use by In-vehicle displays.
(3) The ability for the outputs to have a variety of uses ranging from providing journey time information to providing Drivers with commands for unexpected speed or lane use.
(3) The ability to use several different technologies to provide the outputs but not through any in-vehicle technology as this will be provided separately.
(4) The ability to accommodate through non-functional mechanisms the differentiation between the way that information and commands are provided to Drivers according to the demands of the particular implementation.
(5) The ability to monitor all of the outputs and revisions to any already being output that are likely to give rise to inconsistent and incoherent messages being displayed to Drivers.

Functional Requirements

(a) when the msg (message) request data flow is received from the Inter-urban Traffic Control function, or any of the data flows from the vehicle is received, their contents shall be implemented
(b) the implementation required in (a) shall be achieved through the output of the data flows to drivers and to the Send Messages to Approaching Inter-urban Vehicle function in the inter-urban data for approaching vehicles data flow and to the Manage Vehicle Communication to Driver function through the inter-urban c&i messages data low
(c) the response to (b) shall be sent to the Inter-urban Traffic Control function using the msg response data flow
(d) if the response from (b) is that the data flow has not been output to drivers, data shall be sent to the Maintenance Management functionality using the msg equipment fault data flow
(e) when the incident warning msg or urban crossing messages data flows are received, they shall be implemented as in (b) to (d) above
(f) the contents of the outputs in (b) shall be monitored and any that might lead to inconsistent or incoherent messages being displayed to drivers, revised
(g) if the inter-urban c&i display error data flow is received, check its contents to see if a difference has been found
(h) if a difference has been found then send a device failed indication in the inter-urban c&i device status and inter-urban traffic management c&i response data flows.

Diagrams

The Diagram(s) is (are) the diagram(s) where you can find the function :
  • DFD 3.1.2.14 Implement Inter-urban Management Traffic Strategy
  • Functional tree 3.1

    • Parent Higher Level Function

    Input logical dataflows

    Output logical dataflows

    User needs

    Number

    Description

    7.1.0.11
    The system shall be able to manage traffic in all or part of the road network using a methodology that is appropriate for motorways, e.g. no junctions and pedestrian facilities, but with lane use management.
    7.1.0.2
    The system shall be able to implement identified control strategies that conform with specified policy.
    7.1.0.3
    The system shall not do anything to reduce road safety.
    7.1.0.5
    The system shall manage road traffic in such a way that congestion (travel time) may be reduced.
    7.1.3.4
    The system shall be able to activate control devices (e.g. traffic lights, VMS), either individually or in groups.
    7.1.4.2
    The system shall be able to provide ramp metering (e.g. using traffic signals or barriers) at selected locations (e.g. slip road entrances to high speed roads).
    7.1.4.3
    The system shall provide Tidal Flow Control (reservation of lanes for exclusive use in one direction for a period, then the other direction for another period, on parts of the road network).
    7.1.4.8
    The system shall be able to provide co-ordinated traffic management operations during periods of mass movement across (many) regions.
    7.1.4.9
    The system shall be able to provide specific traffic management for exceptional vehicles (e.g. very dangerous cargo, wide loads, etc.).
    7.1.5.1
    The system shall be able to provide control measures to protect road maintenance work and workers.
    7.1.5.3
    The system shall be able to change the direction of traffic flow on a some or all of the lanes on a carriageway in an orderly manner so that it does not create a safety hazard to any road user.
    7.1.5.5
    The system shall be able to close roads and advise drivers of a suitable diversionary route for a period of time.
    7.1.5.6
    The system shall be able to command drivers of certain classes of vehicle (e.g. heavy vehicles or tourist traffic) to take an alternative route for a period of time.
    7.1.7.1
    The system shall be able to show the maximum authorised speed of vehicles on selected carriageways to be shown to drivers.
    7.4.1.30
    Motorcycle Warning - The system shall be able to detect that the host motorcycle has fallen onto the road pavement, and send this information to a road-side device.
    7.4.1.38
    Hazardous Location Notification - The system shall be able to warn drivers, via a road-side device, of adverse driving conditions ahead (e.g. slippery road, low visibility, queuing traffic) and advise on the appropriate action (e.g. speed).
    7.4.1.42
    Hazardous Location Notification - The system shall be able to inform drivers, via road-side devices, of obstacles in the carriageway and advise on the appropriate action (e.g. speed and lane).
    7.4.1.46
    Hazardous Location Notification - The system shall be able to estimate the condition of the road surface in the vicinity of the host vehicle and send warnings to a road-side device.
    7.4.8.9
    The system shall enable the driver of the host vehicle to be advised, via an in-vehicle device, not to enter a zone defined by virtual cones.
    7.5.1.5
    The system shall be able to manage the traffic in an area using a number of local semi-autonomous traffic management units, whose rules can be modified when required.