1. 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

2. Major Components of Software Package
DTALite: Open-source Assignment/Simulation Engine
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
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 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.

3. 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

4. Sample Vehicle Plot

5. Sample MOE Display

6. Sample Link MOE Plot

7. Sample Vehicle-path Analysis Plot

8. 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

9. Install NEXTA for DTALite (1)
Step 1: Install NEXTA
“C:\Program Files\NEXTA_for_DTALite”
Step 2: Install Visual C 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.

10. Install NEXTA for DTALite (2)
Remarks:
You need an Administrator account to install the NEXTA package.
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.
Please visit
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.

11. Details at Installation Folder
Dynamic Traffic Assignment Engine
Datasets
Graphical User Interface

12. 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

13. Exercise 1: Visualization
What we will learn:
Step 1: Import Data from Excel Spreadsheet
Step 13: Multi-link Comparison
Step 2: Save a project
Step 14: Network-level MOE
Step 3: Run Traffic Simulation/Assignment
Step 15: Vehicle-path Analysis
Step 4: Resize the Network
Step 16: Find Paths in NEXTA
Step 5: Double-Click a Link to Show Link Property
Step 17: View Summary.log
Step 19: Change Link Capacity
Step 6: Display Capacity and Demand Attributes
Step 20: Save the changes
Step 21: Re-run Simulation
Step 7: Select Display Mode to View Simulation Results (Density, Speed, Queue and Volume)
Step 22: Save to Another Folder
Step 23: Re-load previous dataset
Step 24: Compare Capacity Change Visually
Step 8: Select Vehicle Display Mode
Step 25: Compare Network MOEs
Step 9: Show Simulation Results at a Given Time Period
Step 26: Run Simulation: Check Network-level MOE
Step 10: Play Animation
Step 27: Check Link-level MOE
Step 11: Double-Click a Link to Show MOE Profile
Step 28: Locate Other MOE files
Step 29: Read On-line Document
Step 12: Configure MOE Display Dialog

14. 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.

15. Step 2: Save a project
Suggested folder
C:\DTALite\DataSets\Sample2

16. Step 3: Run Traffic Simulation/Assignment

17. 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

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

19. Step 6: Display Capacity and Demand Attributes
Display link capacity
Display OD volume

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

21. Step 8: Select Vehicle Display Mode

22. Step 9: Show Simulation Results at a Given Time Period
First number is current time stamp
Second number is simulation horizon
Clock Bar
Slider

23. Step 10: Play Animation
Rewind, play, pause, stop
Remarks: Simulation clock is advanced in 1-min interval

24. 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)

25. 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 color

26. 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.

27. Step 14: Display Network-level MOE

28. 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

29. Step 16: Find Paths in NEXTA
Define Origin
Define Destination
Find Paths

30. Step 17: View Summary.log

31. Step 18: Change Link Capacity
Change capacity from 900 into 800

32. 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

33. Step 20: Save the changes

34. Step 21: Save to Another Folder
C:\DataSets\Sample\After_Increase_Demand\After_Increase_Demand.dlp

35. Step 22: Re-run Simulation

36. Step 23:Re-load Previous Dataset
Window Tile Vertically

37. Step 24: Compare Capacity Change Visually

38. Step 25: Compare Network MOEs

39. Step 26: Run Simulation: Network-level MOE

40. Step 27: Run Simulation: Link-level MOE

41. Step 28: Locate Other MOE files

42. Step 29: Read On-line Document

43. Advanced Topic 1:
Scenario Configuration
Locate major output files

44. Step 1: Configuring DTASettings.ini
Global multiplication factor will multiply each OD pair by that factor.

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

46. Step 2: View AssignmentMOE.csv
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
The simulation results can be divided into three types: the individual link performance, vehicle trajectory and network performance.

47. Step 3: LinkMOE.csv Iteration From-node ID To-node ID
Timestamp in minute
Travel time in minute
Delay in minute
Link volume in vehicle
Link volume in vehicle/hour/lane (vehphpl)
Density in vehicle/mile/lane
Speed in mph
Exit queue length
Cumulative arrival count
Cumulative departure count

48. Step 4: Vehicle.csv Iteration Occupancy Vehicle ID Information type
Origin zone ID
Value of time
Destination zone ID
Minimum path cost
Departure time
Distance in mile
Arrival time
Number of nodes
Complete flag
Node id
Trip time
Node arrival time
Vehicle type

49. Advanced Topic: Import and Change Time-dependent Demand
Sample time-of-day demand profile

50. Running Simulation: Change OD Demand Distribution