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Project Pane

3.2 Project Pane

The ASSIGN Project Panes includes the following Sections:

  • Project Pane for the Assign-Setup and Assign-Output Tab

    • Networks Section

    • Network Input Section

    • Sites (& CCGs) on Network Section

    • Route Input Section (shown when a Route is selected)

    • Sites (&CCGs) on Route Section (shown when a Route is selected).

Refer to the SIDRA INTERSECTION User Guide for Route Input; Sites (&CCGs) on Route and Sites (& CCGs) in Network.

  • Project Pane for the Volume Store-Assign Volume Bin Tab

    • Assign Volume Bins Section

    • Assign Bin Input Section.

3.2.1 Networks Section

Assign Networks are listed in the Networks Section of the Project Pane together with Basic Networks. Assign Networks and Basic Networks use different icons. Use the Networks Section to select Assign Networks.

3.2.2 Network Input Section

Input Dialogs for an Assign Network are accessed from the Network Input Section of the Project Pane. If an Assign Network is selected, the following Input Dialog buttons will be shown in the Network Input Section:

  • Network Data

  • Network Scenarios

  • Define CCGs

  • Network Timing

  • Assign Data

  • Assign Scenarios.

Assign Data and Assign Scenarios are described in succeeding sections. Refer to the SIDRA INTERSECTION User Guide for information on Network Data, Network Scenarios, Define CCGs and Network Timing dialogs. Network Demand & Sensitivity is not available for Assign Networks.

Assign Data

Assignment Parameters

There are four options for Assignment Method:

  • All-or-Nothing Assignment (AON)

  • Incremental Assignment (IA)

  • User Equilibrium Assignment (UE)

  • Stochastic User Equilibrium Assignment (SUE).

Fixed Route Assignment (FRA) is available with any of the above option.

The Minimum Site Movement Demand parameter applies to all Assignment Methods. A small non-zero volume (Default = 1 veh/h) is required to calculate Route travel time and cost for each Movement Class. This parameter ensures that a minimum Site Movement demand value is applied for each Movement Class.

The Convergence Parameters are specific to each Assignment Method.

  • All-or-Nothing Assignment does not have a convergence parameter

  • Incremental Assignment Convergence Parameter is the Number of Increments (Default = 10).

  • User Equilibrium Assignment Convergence Parameters are:

    • Maximum Number of UE Iterations (Default = 20)

    • Duality Gap Convergence Tolerance (Default = 1%)

  • Stochastic User Equilibrium Assignment Convergence Parameters are:

    • Maximum Number of SUE Iterations (Default = 20)

    • Travel Time Coefficient (Default = -1.0)

    • Max Number of New Routes per Iteration (Default = 5)

    • Duality Gap Convergence Tolerance (Default = 1%).

Fixed Trip Proportions

A Fixed Trip Proportion is the Fixed Route's share of the total Fixed Trips between an O-D pair. All viable Fixed Routes will be listed in the Fixed Trip Volume Proportions table. Any Network Route can be used as Fixed Route if the Network Route connects an O-D pair. Only Routes that satisfy this condition are listed in the table. To enable a Fixed Route for a Movement Class, tick the checkbox in the Apply Column. Fixed Trip Proportions of all enabled Fixed Routes for an O-D Pair must add up to 100% for each Movement Class. Use the Movement Class Filter to manage the visible Movement Classes in the table.

Assign Scenarios

Assign Scenarios define the O-D Volumes and Initial Vehicle Volumes for the Assign Network. Assign Scenarios IDs and Names can be specified. There must be no duplicate Assign Scenario IDs in an Assign Network. Tick the radio button in the Analyse column to select the active Assign Scenario.

Initial Vehicle Volumes can be set to None or to Use Site Volumes. Site Volumes is determined by the active Network Scenario defined in the Network Scenarios dialog. The O-D Volume can be selected from any O-D Volume in the Assign Volume Bin of the Assign Network.

Pedestrian Movements and Volumes specified for the Network Sites always applies.

3.2.3 Assign Volume Bins Section

Assign Volume Bins are listed in the Assign Volumes Section of the Project Pane.

3.2.4 Assign Bin Input Section

Input Dialogs for the Assign Volume Bin are accessed from the Assign Bin Input Section of the Project Pane. If an Assign Volume Bin is selected, the Assign Bin Setup and O-D Volumes buttons will be shown in the Assign Bin Input Section.

Assign Bin Setup

Bin Data

The Bin Data Tab includes Bin Name, Bin ID and Bin Title fields. The Bin ID is required to be unique within the Project File. Information is available on the Number of Zones and Number of O-D Volumes defined for the Bin. Assign Networks that use the Bin are listed in the Linked Assign Networks Table.

Movement Classes

The active Movement Classes for the Assign Volume Bin is set in the Movement Classes Tab. Tick the checkbox to include a Movement Class for the Volume Bin. Movement Classes that are not active will not be applied for traffic assignment, but they can be used as Initial Vehicle Volumes.

Zone Data Editor

The Zones are defined in the Zone Data Editor Tab. It includes entries for Zone ID, Name and Title. Zone IDs must be unique for an Assign Volume Bin. Zones can be Added, Cloned and Deleted, as well as re-arranged in the list using the Move Up and Move Down buttons.

New Zones could be created for the Assign Volume Bin. The new Zones need to be connected to the Assign Network. Zones of Assign Volume Bins that are linked to an Assign Network could not be deleted. The Assign Volume Bin needs to be unlinked from all Assign Networks first, before a Zone could be deleted. To unlink an Assign Volume Bin, replace the Assign Volume Bin with another Bin using Modify Assign Network.

Properties

Bin Information field is available in the Properties Tab. Use this field to record notes regarding the Assign Volume Bin. Bin Attributes are also noted in the Properties Tab, including information on Bin Type, Drive Rule, Units, First Created and Last Modified.

O-D Volumes

The O-D Volumes dialog is for the following:

  • Creating and deleting O-D Volumes as well as editing O-D Volume Properties (ID, Name and Unit Time)

  • Editing Assign O-D Volumes

  • Editing O-D Volume Growth Rates.

O-D Volumes in Bin

An Assign Volume Bin can contain several O-D Volumes. The plus button creates a new O-D Volume in the O-D Volumes in Bin section. The clone button creates a copy of the selected O-D Volume. The delete button erases the selected O-D Volume. O-D Volumes in the O-D Volumes in Bin list can be click-and-dragged up and down the list to change their position in the list.

The pencil button next to the O-D Volume opens the Edit O-D Volume Properties dialog to set the following data for the O-D Volume:

  • Name

  • ID

  • Unit Time (i.e. unit time of the number of Trips for Assign and Fixed O-D Volumes).

New O-D Volume Calculator

The calculator button opens the New O-D Volume Calculator. The Calculator creates a new O-D Volume using existing current O-D Volumes as basis. There are two calculation methods:

  • Apply Growth Rates to Trips in Individual O-D Volume(s): Growth Rates specified in the Assign and Fixed O-D Growth Rates are used to calculate a new O-D Volume for each selected O-D Volume(s). The new O-D Volume(s) will be created, and its ID and Name will be set programmatically.

  • Combine Trips from Multiple O-D Volume(s): A new O-D Volume is calculated by adding Trips of selected O-D Volumes. In the Create Combined O-D Volume section, new O-D Volume's ID and Name can be specified. The new O-D Volume's Unit Time for Volumes and Growth Rate Settings will be copied from the specified "O-D Volume to be Used for Settings of New O-D Volume".

Growth Rates and Growth Rate Settings defined in the Assign and Fixed O-D Growth Rates tab of the O-D Volumes selected for basis of calculation are applied if the Apply Growth Rates is applied. There are options on Growth Model, Number of Years and Round-Off to the Nearest Integer.

Assign O-D Volumes

Assign Trips are entered in the Assign O-D Volumes tab. The Movement Class of the Assign Trips is selected from the Movement Class options on the left-hand side of the dialog. There are three matrix Types to select from. The Square Matrix has Origin Zones as row headers and Destination Zones as column headers. Column Matrix can either have Origin Zones or Destination Zones as the primary header column, i.e. Column Matrix (O-D) and Column Matrix (D-O) respectively.

Multi-selection of cells in the Matrices is enabled using Ctrl-Select. Ctrl-A selects all cells. Ctrl-C copies selected cells to clipboard and Ctrl-V pastes values to cells. Cells from a spreadsheet can be copy-pasted in the Matrices. Use the Copy O-D Volumes to Clipboard to copy all Trip values for pasting to a spreadsheet or another Matrix. To reset selected cells to zero, press Delete, e.g. Ctrl-A then Delete resets all cells to zero.

Assign O-D Growth Rates

Growth Rates of Assign Trips are entered in the Assign O-D Growth Rates tab. The Movement Class of the Growth Rates is selected from the Movement Class options on the left-hand side of the dialog. Three options of Growth Rates include setting Growth Rates for Generation only, Attraction only, or for both Generation and Attraction (i.e. Furness Method). Use the Quick Input feature to apply the selected entry to other O-D Volumes.

Growth Rate applies to Generation means that the Growth Rate specified for the Zone will apply to all Generated Trips by the Zone. Similarly, Growth Rate applies to Attraction means that the Growth Rate specified for the Zone will apply to all Attracted Trips to the Zone.

The Furness Method applies Generation and Attraction Growth Rates to the Generated and Attracted Trip Total of each Zone. The Furness Method then calculates a new Trip Matrix from the current Trip Matrix that satisfies the Generated and Attracted Trip Total of each Zone. Furness Method is an iterative method, and its terminating conditions is defined by the Furness Method Settings: Percentage Stopping Condition and Maximum Number of Iterations. If the maximum percentage change in Generation or Attraction of any Zone between successive iteration is less than the Percentage Stopping Condition the Furness Method is terminated and the final Trip Matrix solution is adopted. The Furness Method iteration is also terminated if the Maximum Number of Iterations is reached and the last Trip Matrix solution is adopted.

Fixed O-D Volumes

Fixed Trips are entered in the Fixed O-D Volumes tab. The Movement Class of the Fixed Trips is selected from the Movement Class options on the left-hand side of the dialog. The user interface for Fixed O-D Volumes is similar to the user interface of Assign O-D Volumes (refer to the Assign O-D Volumes section).

Fixed O-D Growth Rates

Growth Rates of Fixed Trips are entered in the Fixed O-D Growth Rates tab. The Movement Class of the Growth Rates is selected from the Movement Class options on the left-hand side of the dialog. Growth Rates are entered in a square matrix, wherein the Origin Zones are row headers and Destination Zones are column headers. The Fixed Trip Growth Rates are specified per O-D Pair.