Lab 12 - Aimsun Network Building PDF

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Summary

Dr. Vikash V. Gayah lab instructions and walkthrough...

Description

The Pennsylvania State University Department of Civil and Environmental Engineering

Fall 2020

CE 423: Traffic Operations Aimsun (Network Building) Previous labs have described increasingly complex methods that can be used to model operations at signalized intersections. This ranged from the Highway Capacity Software implemented on its own and within a graphical platform (Synchro), as well as a method to simulate vehicle movements (SimTraffic). This lab will focus on the latest simulation techniques using the micro-simulation software, Aimsun, which can be used to study vehicle behavior at signalized intersections, arterials roadways, rural roadways, freeways or any other roadway type. Objectives The primary objective of this lab is to create the downtown State College network (Atherton St between College Ave and Beaver Ave) to simulate traffic moving throughout the network. Aimsun set-up: There are several steps required for opening and setting up the software before traffic inputs are created and entered. The following describes the process. 1.

Start Aimsun 8.2 software on the Desktop

2.

Start a new project: To begin a new project, go to File > New • Change the “Folder” destination to where you plan to save the project (click the “…” to select the folder) • Enter a project name. Example: State College Network • Keep all other default information • Click “OK”

3.

Obtain a map image: To faithfully recreate the network being modeled, we first need to identify an image that can be imported into the software. To do this, you need to download a map from Google Earth (Desktop. Not chrome.). First, locate State College in Google Earth and make sure the entire study site (Beaver Ave and College Ave between Atherton St and Allen St) is within the screen. Before saving the image from Google Earth, go to View > Reset > Tilt to ensure that the image is not tilted and we have a clear top-down view. Then go to file>save>save image. Above where it says “Untitled Map, click “Save Image…” and save it. Then, we need to have a known distance within the network to scale the image in the Aimsun software. To do this, measure a diagonal distance on the map to use as a reference point when importing into Aimsun. Also measure the height and width of the image.

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4. Import image into Aimsun: To import the Google Earth Image into Aimsun, go to File > Import > Image File. Then select the image you saved.

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Change units to “Physical Size.” Put in height and width measured from Google Earth. Use Meters!!!

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Check the diagonal point measure to make sure scale of the image is correct i. “Create a Section”, draw it between reference points, double click, right click, properties, length is at the bottom of the pop-up dialogue box. Delete the section once you compared its length to your reference.

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Once the image is scaled, you need to lock the image so it does not accidently get moved or edited. To do so, double-click on the “Images” in the layers and unselect “Allow Object Editing” The distances do not have to match up exactly, but if it’s super wrong, get a new map from google earth, re-measure the distances and start a new Aimsun project. Don’t just continue on with the lab.

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5.

Change units to English: Need to change units from Metric to English. Go to Edit > Preferences. Click the “Localisation” tab and change “Units” to “English.”

Create network geometry: The next step is to use this image to recreate the roadway network geometry within the Aimsun software. For the purposes of this lab, the network limits are Atherton St between College Ave and Beaver Ave.

1.

Adding road sections: On the left side tool bar, use the “Create a Section” tool • Left click on map to start a section, double click to end the section. Create road sections for the network with breaks where the intersections are located.

Break where intersections are

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2.

Changing road direction: Need to make sure travel direction of road is correct. Arrows on the road section indicate the direction of travel. To change direction, click on road, then right click on road and select “Change Section Direction.” For segments that travel in both directions, pick one for now, don’t generate opposite direction yet.

3.

Change number of lanes: The default number of lanes is 2. To change the number of lanes, left click on road, then right click on road. Go to “Number of Lanes,” and select the appropriate number of lanes.

4.

Assigning road types to sections: Need to assign road types to the segments. To do so, left click on segment. Right click on road section. Toggle to “Road Type” and select “Primary”

5.

Change the lane width: To change the lane width, left click on road, then right click on road. Toggle to “Lane Width.” Type in appropriate lane width. Change Road Type before changing Lane Width!

6.

Change the speed: To change the speed of each segment, left click on road, then right click on road. Toggle to “Speed.” Input speed as mi/hr.

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CE 423 – Fall 2020 Create a curve section: To create a curve within one of the sections, use the “Create a New Vertex (Curved Segment)” tool . • To add a curve, click road section that you want a curve in. Click the “Create a New Vertex (Curved Segment)” tool. Click and hold down mouse where you want the curve (parallel to the road section) and drag across the road. One way to think of this is creating a slice through the road where you want the curve.

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Drag the circle to create the curve.

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8.

Create two-way road: To create a two-way road, left click on the road section, then right click on the road section. Click “Generate Opposite Direction.”

9.

Create a side lane: Left click on road section. Drag the second dot out of the lane. (Channelized right turn from College to Atherton)

10. Intersection (node) creation: Intersections between the sections need to be created. Aimsun refers to intersections as “nodes.”

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To create an intersection, use the “Create a Node” tool Click on the road sections around the intersection. Use the “shift” key to select multiple sections.

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After all road segments are selected, click the “Create a Node” tool.

11. Add a yield movement: After the intersection is created, left click on the road segment. Toggle over the turning movement so the appropriate movement is highlighted in red.

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Right click on nodes. Toggle to “Warning” and click “Yield”

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Need to place the stop bar for the yield movement. Toggle over turning movement arrow. Right click on node. Toggle to “Stop Lines” and click “New.” o Can adjust the placement of the stop bar by clicking and dragging on it.

12. Network should look similar to this:

Create solid lines: Solid lines indicate areas where vehicles are not supposed to switch lanes. In the State College network, this mainly occurs at intersection. 1.

Create solid line: To create a solid line, use the “Create a Solid Line” tool . Click on the dashed line where the solid line should go. The length of the solid line can be altered by clicking and dragging the node.

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Add traffic state: To input traffic into the simulation, you need to add a traffic state that represents the demand in the network. This is done using the flows. 1.

Add a new traffic state: To add a new traffic state, go to “Project” on the top tool bar. Then, “New” > “Demand Data” > “Traffic State”

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A new traffic state will appear on right side of you screen in the Project tool bar. Double-click on the traffic state to change properties. Change “Vehicle Type” to “Car.” Change the “Initial Time” to “4:00:00 PM.” Add the flows to each section.

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Click on the “Turn Info” tab. Input the turn percentages for each movement.

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Add traffic demand: Need to add the traffic demand based on the Traffic State that was just created. 1.

To add traffic demand, go to “Project” on the top toolbar, then ”New” > “Demand Data” > “Traffic Demand”

2.

Double-click on the new Traffic Demand created in the Project window on right of the screen. • In the screen that pops-up, change “Type” to “States” • Click “Add Demand Item” towards bottom of the box • Select the Traffic State that was previously created • Click “OK”

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Preview the simulation with the traffic demand: Before inputting traffic signals, preview the simulation. 1.

To create the traffic simulation, go to “Project” on the top toolbar, go to “New” > “Scenario” > “Dynamic Scenario”

2.

The scenario was added on the right of the screen in Projects. To create an experiment, right-click on the scenario that was just created. Select “New Experiment”

3.

Need to select the Traffic Demand to use. To do so, double-click on “Dynamic Scenario” and change “Traffic Demand” to the Traffic Demand created.

4.

Need to create a “Replication” to run the simulation. Right-click on the “Micro SRC Experiment” > “New” > “Replication.” Click “OK” in the box that pops up.

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5.

Right-click on the Replication that was just created and click “Run Animated Simulation (Autorun)”

6.

This toolbar will appear on the screen or at the top of the screen:

Create traffic signals: The simulation should have roads and vehicles but as you can see, vehicles do not necessary stop at the intersection. You need to create the traffic signals at all the intersections to simulate their behavior. 1.

Create signal groups: The first step to creating traffic signals is to create signal groups. Double-click on the intersection. On the screen that pops up, click the “Signal Groups” tab. • Create a “New” signal. Select the movements that are associated with that signal under “Turns.” Select “OK.” Add new signals, where appropriate. (Reminder: the right turn from college to Atherton is yield controlled, not signal controlled.)

2.

Create phases: To create the phases and traffic control plan of the traffic signal, go to “Project” on the top tool bar, then “New” > “Control” > “Control Plan.” The new control plan will be added on the right side

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CE 423 – Fall 2020 of the screen under Projects. Rename the control plan by right clicking on it. Please name them so you don’t get them mixed up. You’ll have a different control plan for each intersection.

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Double-click on the control plan. Set the “Initial Time” to 16:00:00 (which is 4:00 PM). Click “OK”

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Click on the signalized intersection. Go to “Edit Control Plan” > then click on the name of your plan.

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Change “Type” to “Fixed.” Change “Yellow Time” to time of the yellow signal on the signal plan. Change the “Cycle” length to “100 secs.” Change the “View as” to “Signal Groups” Input the “Start Time” and “Duration” for each phase. The Duration is the total time of the green period. The first signal should start at Start Time of “0”. The next phase starts at the end of all red period for the previous signal. Click “OK.” This should be repeated for each traffic signal in the network.

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Create master control plan: 1.

To create a master control plan for the set of signals, go to “Project” on the top tool bar, then “Control” > “Master Control Plan” • The new master control plan was added to Project area on the right side of the screen

2.

Right-click on that new master control plan. Rename the plan.

3.

Double-click on the Master Control Plan. Change the “Initial Time” to “4:00:00 PM” and the “Duration” to “01:00:00” • Click “Add Control Plan Item” • Select all the created traffic signals • Click “OK”

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Run simulation: A simulation can now be run with the master control plan that was created with the traffic signals. 1.

To run the simulation using the master control plan, double-click on the “Dynamic Scenario” under the Scenarios on the right-side of the screen. • Change the “Master Control Plan” from “None” to the master control plan you created.

2.

Right-click on the “Replication” that was previously created under the Scenario. Select “Run Animated Simulation (Autorun)”

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Deliverable For the deliverable, create the road network with all appropriate inputs (signal timing, volume, etc.). The road network to create in Aimsun is Atherton St from College Ave to Beaver Ave (include Atherton-College and Atherton-Beaver intersections). Submit the Aimsun file, including a summary of the input information used to build the simulation. Include work allocation.

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