This article goes through the process of using an existing strategic transport model in CUBE Voyager to create a mesoscopic transport model in CUBE Avenue, thereby moving from a macro to meso scale.  

Mesoscopic Models are generally used for congestion corridor analysis at regional subareas or at a corridor level. Among the outputs of a Mesoscopic Model with CUBE Avenue we have:

• Volume, Queues, Delays by time segments
• Vehicle Movement Animation
• Animated band-width maps
• Animated Queue maps
• Post-processing for toll or managed lane modeling

The procedure we will take in this article consists of four main steps:

1. Reviewing the Macro Model Highway Network and adding elements.
2. Sub-Area Extraction and Sub-Matrices Extraction
3. Create a Simple CUBE Avenue Model in CUBE 6
4. Analyze Model/Review Outputs

Let's get started.

1.    Reviewing the Macro Model Highway Network and adding elements.

 Open from the tutorial model download (A very simple 25-zone Model created for this demonstration) the Macro2Meso(.cat) Catalog File 

• Right click on Highway and click on the ‘Hide unused files for Program’ to Unhide them

• Right Click on the Path File (*.PTH) and click ‘Auto Name Chosen File’. (Select Yes if asked to create new files in the directory).

If we select the Hide unused files for Program the Path File should continue to be visible.

• Open the Script file (.S) by double-clicking
• Add the following to the PATHLOAD statement:

(remember the comma if going on a separate line)

• Run the program by double-clicking on Highway.

2.    Sub-Area Extraction

• Open the Highway Network (.NET)
• Go to ‘Drawing Layer’ and ‘Under Edit Polygon’ select ‘New’. Draw your Polygon

If your Polygon needs to be edited, click on Restore this will allow you to drag around the points to its new location.

 

Once you have the polygon ready

• Go to the ‘Sub-Area Extraction Option’ under ‘Polygon Tools’
• Save your Network

A ‘Sub-Area Extraction Node Renumbering’ window will pop-up. (You can keep the default numbers for the ‘Renumber Option’ or change them).

You will need a corresponding matrix to be the input of the sub-area. To do this:

• Select the ‘Extract Sub-Area Matrix from Path File’ and click on the folder symbol next to Path File to browse for the previously created PATHFILE. Make sure you’re in the right model folder!

• Click on OK and when asked to overwrite network click Yes.

If we look in our ‘Base’ folder we will now find a network (.net) and a matrix (.mat) for our sub-area.

If we open the Network file we can see what our sub-area looks like. You can play around with the Post Node tools to change the display of the sub-area (e.g. Show number of zones)

 

3.    Create a CUBE Avenue Model

• Launch the Avenue Module

Once the Module is launched, we need to select the inputs and create 2 output files.

• Right click on the matrix file and ‘Link to File’. Then select the file created earlier.

 

• Repeat the same procedure to Link the input Network.

The output files will be a Network file and a Packet Log (*.LOG) file.

• Right click on both files and ‘Auto name Chosen File’

A good practice is to always create a Print File too, therefore repeat the same procedure for the (*.PRN) file as well

After ‘Hiding Unused Files’ the model will look like this:

To create the Mesoscopic Model:

• Open the Highway Script and copy the section from PARAMETERS to ENDRUN

• Paste the copied information to the Avenue Script

We will then have to do a few changes to the new script:

Parameters:

• Change COMBINE=AVE
• Add MODELPERIOD=60 (MINS)
• Add SEGMENTS=4*15 (4 time segments of 15 min interval each)

TIP: CTRL+ALT+SPACE to auto-create keyboard

• ADD VEHPERDIST=250 (to compute storage; veh/km/ln)

LINKREAD phase will remain the same.

ILOOP Phase:

• Read Input Matrix
  • Distribute Input Matrix to 4-time-segments
  • Assuming 0.2(20%), 0.4, 0.3, 0.1 proportions over peak period
• Add DYNAMICLOAD (instead of PATHLOAD)
• Add PACKETSIZE=1 (each packet represents 1 vehicle unit)
• Load all time-segments
  • VOL[1]=MW[1], MW[2], MW[3], MW[4]

• Save the script file and RUN the Avenue program (requires an Avenue license or Bentley account with demo license entitlement)

 

4.    Analyze Model/ Review Outputs/ Animation

• Open the Network file and click on one of the links to open the link’s attribute table

 

 

For each link we will have 4 volume sets for each time segment. This means that VS1_1 in the table shows I will have 11.55 vehicle units for the first 15 minute time segment and so on for the rest of the volume sets.

In the table you will also find queue information as well as block information for each link.

Avenue allows us to perform an animation:

• Go to the ‘Analysis Tab’ and click on ‘Avenue Packets’ under Animation.
• Browse to you .LOG file and open it.
• A pop-up window will appear telling how many packets were read in the time period (click ‘OK’)
• An animation bar will appear at the top. Click on ‘Start’

The animation will allow you to understand how congestion happens according to the different time segments.

If you need to make changes:

• Click on ‘Pause’ and go to ‘Options’

If for example you only want to see the packets leaving from Origin 1-7 and Destinations 8-11 you can make those changes in the ‘Packet Animation Options’ window.

In this case red packets are originated from zone 1-7 and are going to 8-11.

You can also increase the speed to better visualize and understand bottlenecks in the corridor.

 

 

You can also play around with dynamic bandwidth plots and view volumes at junctions. Go play and have fun!