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TRACKS offers Transport Planners and Engineers a full range transport modelling capabilities:

TRACKS has been built with inter-software compatibility in mind.

Landuse & Data Preparation

This is the group of data editor programs, with the main ones being network and zone (landuse and parking) file editors, supported by a number of less complex editors.

As well as the interactive graphical network editor NEX, there is also a batch network editor NEDIT which alters a network according to a set of commands in a change file.

The zone file is currently built assuming a two variable household category model (generally 25 categories) combined with up to 30 landuse categories for use in regression derived attraction trip end distribution equations. This is the standard approach used in New Zealand.Other models can be made available as required.

Trip End Generation & Distribution

There are a number of trip end models available, with a two variable category model of 25 categories and/or linear regression equations able to be used for generation of total trips.

Distribution of these trips to the various zones to get trip ends can be achieved by combinations of category or regression equations. There is also the option of using an accessibility based formulation to calculate trip ends, although calibration of the appropriate function can be difficult.

Distribution & Modal Split

TRACKS supports the standard gravity model, with trip ends coming from the trip end generation phase. The distribution function is either an exponential function of time, distance or cost, or an empirically derived function with a linear interpolation between points. The program will support either a singly or doubly constrained formulation.

The second type of distribution is the growth factor model, with the Furness procedure supported. Growth factors can be derived from a comparison of two trip end files, or individually entered.

The modal split procedures currently supported in TRACKS are discrete choice modelling, which uses a logit model formulation for a single pass generation distribution and modal split, or just the mode split function. Single or nested models can be developed. Using the nested model, Public transport trips can then be further split into separate modes (such as rail and bus) or simply assigned to the public transport system. The public transport assignment allows multimode trips. Walk and Cycle trips are often derived aswell.

Diversion curve mode split is also available.

Parking Models

In addition to standard distribution models there are a number of specialist models which have been developed to cater for specific situations.

CALM is sensitive to parking charges and location, and additional circulation trips are generated as the parking supply gets used up, and initial demand is not satisfied. In effect it simulates the search patterns used by drivers.

Network Assignment

The standard assignment methods are available, including:

Generally, in cases of light to moderate congestion, the incremental assignment is adequate for most situations, provided sensible loading increments are chosen. Equilibrium assignment is preferable in cases of high congestion, but this procedure cannot be used if intersection delays are specifically calculated as the mathematics are violated.

Link speeds are calculated from volume/delay or speed/flow curves, or from a set of volume capacity formulae. Delays at signalised intersections are based on the Australian Research Report No.123, which is the basis of SIDRA, with phase choice and linking of signals available. Delays at unsignalised intersections are calculated from queuing theory using a modification of Tanners formula.

The total time on a link is calculated as the sum of the progression time along the link and the delay at the intersection. The shortest path is calculated either on the basis of time, distance or cost as defined by the user.

The facility also exists for specified turning movements to be banned, or for additional delays to be incorporated. Shortest path trees can also be output or displayed. Time and distance matrices are built successively as the assignment proceeds, with the final matrices being a weighted average of all increments.

At completion of the assignment, the loaded network is stored for later printing, for inspection using the interactive network editor or for plotting. Screen based presentation of the network in graphics form is available to display the assignment either as link flows, or as intersection turning movement displays. There are also specific outputs for use in the UC-win/Road simulation.

Public Transport

The public transport modules assign public transport trips to the transit system, and calculate fare revenue. The transit network is the same as the road and/or rail network, and transit routes are specified by defining a string of nodes. The generalised cost formulation includes all walk, wait, and ride times, and as well as the fare paid, and any transfer costs that might be incurred. Transfer points, and fare sections are defined at appropriate nodes as part of the route definition and multiple operators are analysed separately. Bus running times are expressed as a function of the loaded network link times and intersection delays or as a user defined time based on timetables.

The outputs from the Public Transport assignment include:

Evaluation

Evaluation of alternatives is the most critical part of the analytical process. The user must be able to quickly check the input data, and to present the results in a way that can be rapidly and accurately absorbed. Not only do the results have to be technically interpreted, but they also have to be presented for those who make the decisions. During the development of TRACKS, considerable attention has been paid to the outputs of programs.

In summary, the major components of the evaluation programs are:

Matrix and File Manipulation

These are the utility programs which allow the various trip, time, distance and other matrices to be operated on, printed, transposed, reversed, blocked, expanded, read, or written. Also available on request is the library of Fortran based subroutines that find, read, or write a matrix. These have been supplied to enable other utilities to be written by the user if required.

aaSIDRA Intersection Micro Simulation

Signalised intersections in TRACKS use the formulation and procedures published in ARR123, and include the modified formula in SIDRA 5. In practice, SIDRA can be used as the front end to prepare the data files that describe the signals operation.

In affect, TRACKS is conducting a SIDRA run for each signal in the loading iteration. Common practice is to use TRACKS to determine how different signal formats affect trip distribution. The new results can be run through SIDRA for more detailed analysis.

UC-Win/Road Network and Traffic Simulation

Gabites Porter Consultants have been working closely with the designers of UC-Win/Road, Forum 8, to develop a package that allows for the seamless transfer of TRACKS outputs to WinRoad animation format. The transformation takes place in the Tracks Network editor, NEX, where a cordon is specified on a loaded network and exported to WinRoad automatically.

MapInfo GIS

TRACKS includes a number of features that convert: