Low Level Function
3.1.1.5.24 Implement Urban Traffic Strategies

Overview

This Function shall be capable of providing the following facilities:

(1)  The provision of traffic management that enable Vehicles to make the most efficient use of the urban road network.
(2)  The automatic implementation of strategies for traffic management in a planned sequence according to the time of day and day of week.
(3) The ability to output data for "stop&go" and/or "commands & information" messages directly to Vehicles so that their contents can be output to Drivers by an In-vehicle display mechanism.
(4) The ability of the Road Network Operator to override the automatic implementation of one or more strategies using inputs made through the HMI provided by the Provide Urban Traffic Operator Interface Function.
(5)  The ability for the automatic strategy implementation to be temporarily overridden by inputs requiring green wave routes to be implemented for selected Vehicles.
(6)  The ability for the automatic strategy implementation to be overridden by requests for changes to the way that traffic is managed that are received from functionality in the Manage Incidents and Manage Demand High-level Functions in the Manage Traffic Functional Area.
(7)  The ability for the Road Network Operator to define the order of priority for the various inputs that can override the automatic strategy implementation.
(8)  The ability to adapt the traffic management strategies to suit the current and predicted traffic conditions using real-time data to identify the need for and content of the adaptations (adaptive traffic control).
(9)  The ability to apply traffic management strategies to some or all of the urban road network managed by the System.
(10)  The ability to monitor the results from the implementation of strategies so that if necessary corrective action can be taken if the content of strategies are not followed.
(11) The provision of  details of the current and previously implemented strategies on some or all parts of the urban road network to the Road Network Operator through the Provide Urban Traffic Operator Interface Function.

Functional Requirements

(a) continuously monitor for receipt of the operator urban traffic management request, planned urban traffic management request, urban environmental inputs, urban demand management strategy and urban incident strategy request data flows
(b) when any of the data flows in (a) is received, implement the traffic management commands that they contain using the contents of the data flow containing urban static data to determine which are the appropriate section(s) if the urban road network to which the commands apply
(c) the commands in (b) shall be implemented using some or all of the urban bridge inputs, urban tunnel inputs, urban lane management, urban speed setting, urban traffic management s&g request, urban traffic management msg requests and urban recommended routes data flows, plus data sent to the Traffic Simulation functionality in the urban strategies in use data flow and data sent directly to In-vehicle functionality using the s&g outputs for driver display and c&i outputs for driver display data flows
(d) the commands being implemented in (b) shall be filtered for applicability and sent to any other adjacent urban traffic management systems in the urban traffic management strategies data flow and to any relevant inter-urban traffic management systems in the urban to inter-urban traffic commands data flow
(e) if the urban zoning strategy data flow is received, whichever is necessary of the data flows in (c) shall be sent plus the urban zone access vehicle list data flow
(f) it shall be possible for the data flows containing current urban traffic conditions, urban traffic flow management data, predicted urban network data, bridge urban inputs and tunnel urban inputs to be continuously monitored and for their contents to be used to revise the detail of the commands being implemented in (b) thus providing adaptive traffic control
(g) if the operator urban traffic management request was received in (a) and had led to the implementation of (b) and (c) then the operator urban traffic management response data flow shall be sent to the Provide Operator Interface function
(h) as a result of (c) the receipt of the urban traffic management s&g response, urban traffic management l&s response and urban traffic management c&i response data flows shall be monitored
(i) when any of the data flows in (h) is received their contents shall be checked to see if the commands in (c) are being followed
(j) if the result of (i) is that the commands are not being followed, this shall be communicated to the Provide Operator Interface function in the operator urban management response data flow and to the Maintenance Management functionality in the urban response fault data flow
(k) if the requirement is included in the contents of the data flows in (b) the contents of the data flows in (i) shall be used to revise the commands being sent in (c)
(l) if either the inter-urban to urban traffic commands or urban traffic management strategy data flows is received, their contents shall be analysed if necessary new commands implemented as in (c) with the addition that requests may be sent to any relevant multi-modal management systems in the urban crossing inhibit data flow
(m) if any of the urban emergency route request, green wave request, vehicle priority request and request demand vehicle priority data flows is received, its contents shall be implemented as in (b) and (c) above and shall take priority over any of the other inputs received in (a), (l) and (m)
(n) of the data flows in (m) the contents of the urban emergency route request shall take priority over all the others, with the contents of the vehicle priority request data flow being the next highest in priority, followed by the contents of the demand vehicle priority data flow
(o) if the inter-urban virtual coned area request data flow is received, implement the necessary lane closures and speed restrictions as in (b) and (c) above in order to prevent vehicles from entering the area around an accident
(p) the commands in the operator urban traffic management request data flow received in (a) shall take precedence over all the inputs in (a) and (l) but not the inputs in (m) and (o)
(q) the commands in the planned urban traffic management request data flow received in (a) shall take the lowest priority after all the other inputs in (a), (l), (m) and (o)
(r) implementation of all the outputs in (c) shall be checked to ensure that the comments being implemented are consistent and coherent and do not contradict each other.

Diagrams

The Diagram(s) is (are) the diagram(s) where you can find the function :
  • DFD 3.1.1.5 Provide Urban Traffic Management Faciliti
  • Functional tree 3.1

    • Parent Higher Level Function

    Input logical dataflows

    Output logical dataflows

    User needs

    Number

    Description

    2.1.2.2
    The system shall be able to develop and implement traffic environmental management strategies based on current and predicted traffic conditions.
    2.1.3.1
    The system shall be able to measure the effect of a strategy, and to modify it when necessary.
    5.2.0.2
    The system shall inform the TCC about the route that is intended for each green wave before it is used.
    5.2.0.3
    The system shall provide the identity of each traffic signal at which priority is needed, and the 'timing window' in which priority is to be given.
    7.1.0.10
    The system shall be able to manage traffic in all or part of the road network using a methodology that is appropriate for urban roads, e.g. using traffic lights at junctions and with the possibility of incorporating facilities for pedestrians to cross the road in a controlled manner.
    7.1.0.12
    The system shall be able to use different methodologies to control separate areas of the road network.
    7.1.0.13
    The system shall be able to manage the urban/inter-urban interface.
    7.1.0.2
    The system shall be able to implement identified control strategies that conform with specified policy.
    7.1.0.4
    The system shall manage road traffic in such a way that levels of environmental (i.e. atmospheric and noise) pollution may be reduced.
    7.1.0.5
    The system shall manage road traffic in such a way that congestion (travel time) may be reduced.
    7.1.0.6
    The system shall be able to help co-ordinate the activities of TICs and TCCs.
    7.1.12.1
    The system shall be able to control pedestrian and cycle crossings.
    7.1.12.2
    The system shall be able to monitor and control pedestrian and cycle crossings in order to optimise their use.
    7.1.4.5
    The system shall be able to provide priority to selected travellers (e.g. PT, emergency vehicles, cycles, pedestrians) through the road network, including on motorways (when applicable).
    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.
    7.1.5.5
    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.
    7.1.5.7
    The system shall be able to recommend re-routing strategies to reduce congestion.
    7.1.5.8
    The system shall request confirmation of all exceptional measures before they are executed.
    7.1.5.9
    The system shall be able to recommend re-routing strategies to reduce atmospheric pollution.
    7.1.9.1
    The system shall be able to provide green wave management for all vehicles.
    7.1.9.2
    The system shall be able to minimise delays of all vehicles using adaptive signal control
    7.1.9.3
    The system shall be able to grant priority to selected vehicles (e.g. PT, emergency vehicles) at an intersection controlled by some form of traffic signals.
    7.1.9.4
    The system shall be able to give priority to PT in a manner that minimises the impact on other road users.
    7.3.1.2
    The system shall be able to recommend alternative routes (e.g. that take into account the needs of heavy vehicles (and hazardous goods)) when it is required to direct certain types of vehicle away from a particular part of the road network.
    7.3.1.3
    The system shall be able to control the access of vehicles into a zone using a form of identification, e.g. electronic tags, number plate readers, etc.
    7.4.3.7
    The system shall be able to advise a driver, via an in-vehicle device, which lane to use when passing an incident/accident.
    7.4.3.8
    The system shall be able to advise a driver, via an in-vehicle device, where to stop safely (e.g. an appropriate exit lane, hard shoulder).
    7.4.5.1
    The system shall enable the TCC to calculate recommended headways for the current traffic and environment conditions.
    7.4.8.7
    The system shall be able to advise the driver, via an in-vehicle device, of an appropriate lane to use to create a “blue corridor”.
    7.4.8.8
    The system shall enable the host emergency vehicle to “place” virtual cones around the site of an accident.
    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.
    7.5.1.10
    The system shall enable the service provided to the traveller to be passed from one TCC to another as the traveller moves from one area of coverage to another.
    7.5.1.25
    The system shall enable the TCC to recommend the use of alternative routes for different types of vehicle.
    7.5.1.26
    The system shall enable the TCC to command the use of alternative routes for different types of vehicle.
    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.
    7.5.2.3
    The system shall enable a traffic signal controller to receive a request for a green phase from an approaching vehicle; in the event that more than one conflicting request is received at the same time they shall be prioritised (e.g. emergency vehicles before private vehicles), possibly by the TCC operator.
    7.5.2.4
    The system shall be able to determine the queue length in front of traffic signals in urban areas.