Traffic and air quality
    Scenario Parameters in SIMTRAP

    This document describes a part of the interface between the SIMTRAP Server and the HPCN Model Server, that runs both the traffic model DYNEMO and the air quality models of the DYMOS system.

    For the syntax of this interface and its implementation details, please refer to the SIMTRAP Architecture Description.

    SUMMARY

    The parameter set defining a useful decision alternative for the user consists of several parts:

    • Explicit Parameters: these are directly accessible to the user and can be edited; they may include selections from (sets of) predefined data sets such as transportation networks or emission inventories. They include:

      • Meteorological parameters
      • Emission parameters including background concentrations and initial values;
      • Traffic related data
    • Implicit Parameters: are stored primarily with the HPCN Model Server and are not directly accessible to the user for editing. They may be shown in the user interface to assist selection from predefined read-only sets (e.g., a road network geometry), or be completely transparent (e.g., internal model coefficients).

    • General Control Parameters: (not yet clarified, might depend on performance) they would define model control parameters such as the overall length of a simulation run (just a few hours around rush hour, one or more days ?) as well as output frequencies.

    Each model scenario contains a complete set of default parameter values; upon entering the scenario selection/editing, there is always a (default) scenario loaded. The user can, but does not have to, make any changes (selection of alternative scenarios, changes to values within a scenario) to the scenario specification as required. These can then be stored, together with the model results, for later analysis or as the basis for future modifications.

    Meteorology

    Data required:

    Several data sets each consisting of time series for

    • Wind Field (speed + direction) in different layers up to at least 4000 m,
    • Potential temperature in different layers (same as above),
    • surface temperatures (soil, water)
    • Cloud Cover
    All data should be available as regular time series at 6-hourly intervals, for at least one location representative for the model domain. Scenario Parameters Passed to Model Server

    Description Parameter Translates into
    Meteorology Scenario scenario ID: string a complete data set indexed by the ID,
    stored at the Model server

    User Interface considerations

    The SIMTRAP server has a list of admissible descriptive meteorology scenario names with associated IDs (dates encoded: YYYYMMDDHHMM representing the starting time of the scenario; absolute dates use the YYYY encoding, synthetic dates use 0000 for the year) along with the following descriptors:

    • starting date,
    • average temperature (over time and space),
    • average wind speed,
    • average displacement (definition?),
    • average cloud cover.

    The user selects a scenario based on the scenario name (ID).

    Alternatively, the user could specify values for any or all of the above characteristics, and the the best fit scenario is retrieved. The user acknowledges, and ID is passed to model server. This requires, however, that either a large set of scenarios, or continuous time series of at least one year of all the above parameters are available at the SIMTRAP server. Please note that in this case, the meteorological time series can also be displayed and analyzed with the time series analysis tools of the ACA ToolKit time series analysis functions.





    Emission

    Data required

    Several data sets each consisting of time series for

    • industrial emission matrices (NO, NO2, VOC),
    • household emission matrices (NO, NO2, VOC),
    • background concentrations (NO, NO2, VOC)
    Scenario Parameters Passed to Model Server

    Description Parameters Translates into
    Industrial Emissions ID: string (descriptive name)
    scale factor: float
    time series of matrices indexed by ID, scaled by factor
    Household Emissions ID: string
    scale factor: float
    time series of matrices indexed by ID, scaled by factor
    Background Concentrations ID: string
    scale factor: float
    time series indexed by ID, scaled by factor

    Please note that for both emission parameters and background concentration, three values for NO, NO2, and VOC have to be specified in each case. An unspecified values indicates the default, i.e., a multiplier of 1.0. User Interface considerations

    Selection of (matrix) time series: GMD must check whether more than one (structurally different) base matrix for industries and households is necessary.





    Road network

    Data requirements

    Nodes and links of the network together with VISUM and DYNEMO attributes (not the trip matrix!). Alternative road network scenarios represent different planning states, e.g., with and without new planned roads implemented. Scenario Parameters Passed to Model Server

    Description Parameters Translates into
    Network Scenario ID: string a complete data set indexed by the ID

    User Interface considerations

    List of IDs is sufficient, as number of alternative network scenarios will in general be small.





    Trip Matrix

    Data requirements

    • several trip matrices for different days of the week
    • difference trip matrices that contain deltas between the trip matrix for an average day and the one for a day with a special event (e.g. football match).
    time of the day??? Scenario Parameters Passed to Model Server

    Description Parameters Translates into
    Day (of the week or special) ID: string a trip matrix indexed by the ID
    Special Event (optional) ID: string
    weight factor: float
    the difference trip matrix indexed by the ID is weighted
    and added to the base trip matrix

    User Interface considerations

    IDs for day of week may also include special days such as Bank Holiday.





    Link Attributes

    Data requirements

    For each link:

    • number of lanes,
    • v-k relation
    • desired speed distribution
    Scenario Parameters Passed to Model Server

    Description Parameters Translates into
    Link Closure (optional) link: linkID nodeID
    from: integer to: integer
    link closure (directly supported in
    DYNEMO *.DST input data), decision cross-sections
    adjacent to closed link
    Link Closure for Vehicle Type (optional) link: linkID nodeID
    vehType: integer
    (no time window)
    link parameters (directly supported in DYNEMO *.DST input data)
    Link Closure for Vehicle Type
    All Links of Specified Type (optional) linkType: integer
    vehType: integer
    (no time window)
    link parameters (directly supported in
    DYNEMO *.DST input data)
    Fewer lanes (optional) link: linkID nodeID
    lanes: integer (<= ORIG. NUMBER OF LANES)
    link parameters (directly supported in
    DYNEMO *.DST input data)
    Reduced Capacity (optional) link: linkID nodeID
    percentage: integer from: integer to: integer
    vWunsch relation, v-k relation
    Speed Limit (optional) link: linkID nodeID
    speed: integer [km/h] (no time window)
    vWunsch relation, v-k relation
    Speed Limit: All Links of Specified Type (optional) linkType: integer
    speed: integer [km/h]
    no time window!
    vWunsch relation, v-k relation

    User Interface considerations

    Links are addressed by a combination of the VISUM link number and the VISUM node number of the source node (to indicate direction unambiguously)





    Global Traffic Parameters

    Data requirements

    • trip matrix,
    • fleet composition,
    • specific events
    • Scenario Parameters Passed to Model Server
    Description Parameters Translates into
    Trip matrix scale factor (optional) factor: float multiply base matrix by factor
    Fleet Composition Change (optional) vehType: integer
    delta: +/- integer [%]
    change fraction of specified vehicle type
    by percentage in all fleet compositions

    User Interface considerations

    The scenario parameter has to be presented to the user in a problem context rather than as a model parameter: instead of Trip Matrix Scaling Factor, for example, the user defines an overall increase in traffic volume. SIMTRAP server translates any of these problem related specifications into the appropriate combination of Link and Trip Link and Trip Matrix scenarios.


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