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
Major Components of Software Package
DTALite: Open-source
Assignment/Simulation Engine
NEXTA: GUI for Visualization
and Data Preparation
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 at
http://sourceforge.net/projects/dtalite/
2
Sample Data Set: Portland Network and
Demand Data
# of Zones = 2,013
# of Nodes = 10,094
# of Links = 25,804
# of Vehicles = 1.1M for 4 hours
Computer Settings:
Intel Core 2 Duo CPU
(2 processors)
2.26 GHz
4 GB of RAM
Total computation time for 10 iterations:
4 hours
Computation time per iteration: 24 min
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Sample Vehicle Plot
4
Sample MOE Display
5
Sample Link MOE Plot
6
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
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Install NEXTA for DTALite (1)
Step 1: Install NEXTA
“C:\Program Files\NEXTA_for_DTALite”
Step 2: Install Visual C++ 2008 redistribution package
Go 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 package
Go 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)
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.
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Details at Installation Folder
Dynamic Traffic Assignment Engine
Datasets
Graphical User Interface
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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
Windows
Windows
Windows
2000
XP
Vista (32 bit/64 bit)
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Exercise 1: Visualization
What we will learn:
Step 1: Import Data from Excel Spreadsheet
Step 2: Save a project
Step 3: Run Traffic Simulation/Assignment
Step 4: Resize the Network
Step 5: Double-Click a Link to Show Link
Property
Step 6: Display Capacity and Demand
Attributes
Step 7: Select Display Mode to View
Simulation Results (Density, Speed, Queue
and Volume)
Step 8: Select Vehicle Display Mode
Step 9: Show Simulation Results at a Given
Time Period
Step 10: Play Animation
Step 11: Double-Click a Link to Show MOE
Profile
Step 12: Configure MOE Display Dialog
Step 13: Multi-link Comparison
Step 14: Network-level MOE
Step 15: Vehicle-path Analysis
Step 16: Find Paths in NEXTA
Step 17: View Summary.log
Step 19: Change Link Capacity
Step 20: Save the changes
Step 21: Re-run Simulation
Step 22: Save to Another Folder
Step 23: Re-load previous dataset
Step 24: Compare Capacity Change Visually
Step 25: Compare Network MOEs
Step 26: Run Simulation: Check Network-level
MOE
Step 27: Check Link-level MOE
Step 28: Locate Other MOE files
Step 29: Read On-line Document
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Step 1: Import Data from Excel
Spreadsheet
• Filename: SampleNetwork.xls
• Dataset folder: C:\Program
Files\NEXTA_for_DTALite\DataSets
• The data structure of the spreadsheet will be
explained in Exercise 3.
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Step 2: Save a project
Suggested folder
C:\DTALite\DataSets\Sample2
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Step 3: Run Traffic Simulation/Assignment
Run Traffic
Simulation/Assignment
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Step 4: Tool bar -> Zoom In /Out, Resize
the Network
View Tools
Distance
Move Network
Pan
Zoom In
Zoom Out
Show Entire Network
Show/Hide Grid
Show/Hide Node
Show/Hide Zone
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Step 5: Double-Click a Link to Show Link
Property
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Step 6: Display Capacity and Demand
Attributes
Display link capacity
Display OD volume
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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
First number is current time
stamp
Clock Bar
Second number is simulation horizon
Slider
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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
Upstream node ->
Downstream node (# link ID)
Green line indicates the
current simulation time
Time axis (unit: min)
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Step 12: Configure MOE Display Dialog
•Select MOE: Density, Speed, Queue Length, Volume
•Start Time, End Time, Max Y
•Export data to Excel
•Change Background colo
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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.
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Step 14: Display Network-level MOE
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Step 15: Vehicle-path Analysis
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
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Step 16: Find Paths in NEXTA
Define Origin
Define Destination
Find Paths
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Step 17: View Summary.log
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Step 18: Change Link Capacity
Change capacity from 900 into 800
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Step 19: Change Demand
Increase overall demand level
Change demand of individual OD pairs
Change OD demand (14)
from 5000 into 6000
Change Overall Multiplication
Factor from 1.0 into 1.5
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Step 20: Save the changes
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Step 21: Save to Another Folder
C:\DataSets\Sample\After_Increase_Demand\After_Increase_De
mand.dlp
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Step 22: Re-run Simulation
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Step 23:Re-load Previous Dataset
previous dataset
Window Tile Vertically
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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
Global multiplication factor will
multiply each OD pair by that factor.
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Running Simulation: Illustration of Demand
Loading/Simulation Horizon, Departure
Time Interval
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Step 2: View AssignmentMOE.csv
1.
2.
3.
4.
5.
6.
7.
Iteration
Time stamp in minute
Cumulative in-flow count
Cumulative out-flow count
Number of vehicles in the network
Flow in a minute
Average trip-time in minute
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Step 3: LinkMOE.csv
1. Iteration
2. From-node ID
3. To-node ID
4. Timestamp in minute
5. Travel time in minute
6. Delay in minute
7. Link volume in vehicle
8. Link volume in vehicle/hour/lane (vehphpl)
9. Density in vehicle/mile/lane
10. Speed in mph
11. Exit queue length
12. Cumulative arrival count
13. Cumulative departure count
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Step 4: Vehicle.csv
1.
2.
3.
4.
5.
6.
7.
8.
9.
Iteration
Vehicle ID
Origin zone ID
Destination zone ID
Departure time
Arrival time
Complete flag
Trip time
Vehicle type
10.Occupancy
11.Information type
12.Value of time
13.Minimum path cost
14.Distance in mile
15.Number of nodes
16.Node id
17.Node arrival time
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Total Amount of Trips
Advanced Topic: Import and Change
Time-dependent Demand
Time-of-Day
Sample time-of-day demand profile
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Running Simulation: Change OD Demand
Distribution
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