Step-by-Step Tutorial NEXTA: Simulation Data Visualizer for

Open-Source DTALite Engine

NEXTA: Network EXplorer for Traffic Analysis

This tutorial is prepared by

Dr. Xuesong Zhou and Mingxin Li at Univ. of Utah

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Major Components of Software Package

NEXTA (Network EXplorer for Traffic Analysis) is a graphical user interface to facilitate preparation, post-processing and analysis of simulation-based dynamic traffic assignment datasets. NEXTA is extended from DYNASMART-P Graphical Input Editor (DSPEd) 1.0, which was initially developed by ITT Industries, Inc. for the Federal Highway Administration (FHWA) in 2004. Dr. Xuesong Zhou has been maintaining and enhancing its capabilities since then. NEXTA is distributed as Freeware, and it is now also used as the visualization program for TRANSIMS, an open-source software package for transportation analysis and simulation.

DTALite is a fast open-source dynamic traffic assignment engine, which aims to assist transportation planners to effectively utilize advanced dynamic traffic analysis tools with limited hardware and time resources. It uses a computationally simple but theoretically rigorous traffic queuing model in its lightweight mesoscopic simulation engine. DTALite is distributed as open-source software using the GNU General Public License (GPL). Its source code is available athttp://sourceforge.net/projects/dtalite/

DTALite: Open-source Assignment/Simulation Engine

NEXTA: GUI for Visualization and Data Preparation

Sample Data Set: Portland Network and Demand Data

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# of Zones = 2,013# of Nodes = 10,094# of Links = 25,804# of Vehicles = 1.1M for 4 hours

Total computation time for 10 iterations: 4 hours

Computation time per iteration: 24 min

Computer Settings:Intel Core 2 Duo CPU (2 processors)2.26 GHz 4 GB of RAM

Sample Vehicle Plot

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Sample MOE Display

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Sample Link MOE Plot

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Sample Vehicle-path Analysis Plot

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Tutorial Outline

Software installation

Exercise 1: View simulation results

Exercise 2: Running traffic simulation and understand output files

Exercise 3: Prepare input data from Excel spreadsheet

Install NEXTA for DTALite (1)

Step 1: Install NEXTA “C:\Program Files\NEXTA_for_DTALite”

Step 2: Install Visual C++ 2008 redistribution packageGo to folder

C:\Program Files\NEXTA_for_DTALite \VisualC++_RedistributionPackage

and click on “vcredist_x86.exe” to install.

Step 3: Install “Data Access Object” redistribution packageGo to C:\Program Files\ NEXTA_for_DTALite\

VisualC++_RedistributionPackage\DISK1, click on “Setup.exe” to install.

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Install NEXTA for DTALite (2)

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Remarks:1) You need an Administrator account to install the NEXTA

package.2) Please save your DTALite data set to a “writable” folder (e.g.

C:\DTALite\DataSets\”. Folder “Program Files” could be set to “read-only” by your Windows operating systems.

3) Please visit http://docs.google.com/View?id=drpjtjx_112d99s3mgc for the

latest NEXTA for DTALite software release and additional data set.

4) The release data of your current NEXTA package can be found at menu -> Help -> About.

Details at Installation Folder

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Graphical User Interface

Dynamic Traffic Assignment Engine

Datasets

Hardware and Software Requirements

Hardware recommendations Minimum memory of 512 MB. Recommended options for large-scale network: 4GB of RAM

Remarks: An insufficient amount of RAM can cause your computer to continually read data from disk instead of physical memory, please ensure there is sufficient memory for very large networks.

Operating system requirements Windows 2000 Windows XP Windows Vista (32 bit/64 bit) Windows 7

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Exercise 1: Visualization

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What we will learn:

Step 1: Import Data from Excel SpreadsheetStep 2: Save a projectStep 3: Run Traffic Simulation/AssignmentStep 4: Resize the NetworkStep 5: Double-Click a Link to Show Link PropertyStep 6: Display Capacity and Demand AttributesStep 7: Select Display Mode to View Simulation Results (Density, Speed, Queue and Volume)Step 8: Select Vehicle Display ModeStep 9: Show Simulation Results at a Given Time PeriodStep 10: Play AnimationStep 11: Double-Click a Link to Show MOE ProfileStep 12: Configure MOE Display DialogStep 13: Multi-link ComparisonStep 14: Network-level MOE

Step 15: Vehicle-path AnalysisStep 16: Find Paths in NEXTAStep 17: View Summary.logStep 19: Change Link CapacityStep 20: Save the changesStep 21: Re-run SimulationStep 22: Save to Another FolderStep 23: Re-load previous datasetStep 24: Compare Capacity Change VisuallyStep 25: Compare Network MOEsStep 26: Run Simulation: Check Network-level MOEStep 27: Check Link-level MOEStep 28: Locate Other MOE filesStep 29: Read On-line Document

Step 1: Import Data from Excel Spreadsheet

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• Filename: SampleNetwork.xls• Dataset folder: C:\Program Files\

NEXTA_for_DTALite\DataSets• The data structure of the spreadsheet will be

explained in Exercise 3.

Step 2: Save a project

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Suggested folderC:\DTALite\DataSets\Sample2

Step 3: Run Traffic Simulation/Assignment

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Run Traffic Simulation/Assignment

Step 4: Tool bar -> Zoom In /Out, Resize the Network

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View Tools

DistanceMove Network PanZoom In Zoom Out Show Entire Network Show/Hide Grid Show/Hide NodeShow/Hide Zone

Step 5: Double-Click a Link to Show Link Property

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Step 6: Display Capacity and Demand Attributes

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Display link capacity Display OD volume

Step 7: Select Display Mode to View Simulation Results (Density, Speed, Queue and Volume)

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Step 8: Select Vehicle Display Mode

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Step 9: Show Simulation Results at a Given Time Period

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First number is current time stamp

Second number is simulation horizon

Clock BarSlider

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Step 10: Play Animation

Rewind, play, pause, stop

Remarks: Simulation clock is advanced in 1-min interval

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Step 11: Double-Click a Link to Show MOE Profile

Time axis (unit: min)Green line indicates the current simulation time

Upstream node -> Downstream node (# link ID)

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Step 12: Configure MOE Display Dialog

• Select MOE: Density, Speed, Queue Length, Volume• Start Time, End Time, Max Y

• Change Background color• Export data to Excel

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Step 13: Multi-link Comparison

Select multiple links (by using Ctrl+ mouse click) to display MOE time profiles simultaneously for multiple selected links, in the same or

different projects.

Step 14: Display Network-level MOE

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Step 15: Vehicle-path Analysis

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OD to paths

Paths to vehicles

Vehicles –to list of links

Select a path from path list to highlight the path on the background network

Step 16: Find Paths in NEXTA

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Define Origin Define Destination Find Paths

Step 17: View Summary.log

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Step 18: Change Link Capacity

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Change capacity from 900 into 800

Step 19: Change Demand

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Increase overall demand level Change demand of individual OD pairs

Change Overall Multiplication Factor from 1.0 into 1.5

Change OD demand (14) from 5000 into 6000

Step 20: Save the changes

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Step 21: Save to Another Folder

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C:\DataSets\Sample\After_Increase_Demand\After_Increase_Demand.dlp

Step 22: Re-run Simulation

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Step 23:Re-load Previous Dataset

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previous dataset Window Tile Vertically

Step 24: Compare Capacity Change Visually

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Step 25: Compare Network MOEs

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Step 26: Run Simulation: Network-level MOE

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Step 27: Run Simulation: Link-level MOE

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Step 28: Locate Other MOE files

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Step 29: Read On-line Document

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Advanced Topic 1:

Scenario Configuration Locate major output files

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Step 1: Configuring DTASettings.ini

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Global multiplication factor will multiply each OD pair by that factor.

Running Simulation: Illustration of Demand Loading/Simulation Horizon, Departure Time Interval

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Step 2: View AssignmentMOE.csv

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1. Iteration2. Time stamp in minute3. Cumulative in-flow count4. Cumulative out-flow count5. Number of vehicles in the network6. Flow in a minute7. Average trip-time in minute

Step 3: LinkMOE.csv

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1. Iteration2. From-node ID3. To-node ID4. Timestamp in minute5. Travel time in minute6. Delay in minute7. Link volume in vehicle8. Link volume in vehicle/hour/lane (vehphpl)9. Density in vehicle/mile/lane10.Speed in mph11. Exit queue length12.Cumulative arrival count13.Cumulative departure count

Step 4: Vehicle.csv

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1. Iteration2. Vehicle ID3. Origin zone ID4. Destination zone ID5. Departure time6. Arrival time7. Complete flag8. Trip time9. Vehicle type

10.Occupancy11.Information type12.Value of time13.Minimum path cost14.Distance in mile15.Number of nodes16.Node id17.Node arrival time

Advanced Topic: Import and Change Time-dependent Demand

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Time-of-Day

Tota

l Am

ount

of T

rips

Sample time-of-day demand profile

Running Simulation: Change OD Demand Distribution

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