VISSIM Tutorial Starting VISSIM and Opening a File Click on the Windows START button, go to the All Programs menu and find the PTV_Vision directory. Start VISSIM by selecting the executable file. The following window will open on your screen. Figure 1 VISSIM Window. Once VISSIM is open, browse to the VISSIM file deakin&6thst.inp in the directory shown to you in lab. 1
STEP 1: Introduction to VISSIM Intersection Features Geometric configuration Once you open the *.inp file, you will see a diagram of roadways appear. In this case, the diagram is of one intersection, Deakin Avenue and 6 th Street. Notice all of the geometric features, such as the number of lanes, types of lanes, and lengths of turn bays. These are all features that you can change, but in this lab you don t need to do this. Signal Phasing Signal phasing in VISSIM works the same way as you learned in class, using NEMA phases. You can specify up to eight phases. Each phase that is specified in VISSIM must be linked to the signal heads that will control the turning movements. Signal heads in VISSIM are the Maroon lines that look like they might be stop bars (see Figure 2). Take a look at the signal heads in the network that you have opened now to determine to which phase each of the signal heads is linked. Signal Heads button Detector button Figure 2. Deakin Ave and 6 th Street Intersection Detectors and Signal Heads. To view the signal heads settings, click on the button indicated by a call out Signal Heads button as shown in Figure 2. Then double click on the signal head in question. The Signal Heads pop-up window will appear as shown in Figure 2. There are several fields in this window. You are looking for the one that contains the number of the phase to which this signal head is linked. VISSIM calls a phase Signal Group. So, you find the phase number to which the signal head is linked in the Signal Group field. 2
Figure 3. Signal Head Window. The fields in the signal head pop-up window as shown in Figure 3 have the following meanings: No. : the index for a signal head; Name : the name for a signal head; Link : the roadway that a signal head is on; Lane : which lane a signal head is on; At : the distance between a signal head and the beginning point of an approach; SC : signal controller index or signalized intersection index at which a signal head resides; Signal group : the phase that a signal head is linked to; Type : signal head shapes, which include circular, left arrow, right arrow, and invisible; Or Sig. Gr. : a second optional phase that a signal head can be linked to; and Vehicle Classes : the vehicle types that obey signal indications displayed by a signal head. Detector Placement Detector placement at this intersection is one detector for each lane as shown in Figure 4. The detector length is 20 feet. They are placed at the stop bar. No advanced detection was used, because all of the intersection approaches are low speed approaches of 25 mph or less. Additional detectors could be used, but only using stop bar detection is OK. 3
Ø4 Ø8 Ø7 Ø1 Ø6 Ø phase detector Phase direction Figure 4. Intersection configuration. To view detector settings, click Detector button as shown in Figure 2. Then double click on the detector in question. The detector pop-up window will appear as shown in Figure 5. There are several tabs in the window, which include Position & Activation, Departure Signal, and Other. View the Position & Activation tab. You only need to modify fields in this tab for this laboratory exercise. Change the detector length by changing the value in the field labeled Length. Make sure the value in the field Before stop is equal to or greater than the detector length. In the field Vehicle Classes, select All Vehicle Types. This will cause the detector in question to detect all types of vehicles, such as passenger cars, heavy vehicles, and buses. However, if you d like to have this detector only detect a certain kind of vehicle, select that particular type of vehicle. The checkbox PT Calling Pt. is about public transit. Similarly, the field PT Lines is about public transit. Neither of them is relevant to this laboratory exercise. See the VISSIM manual for more details if you re interested. After you re done with all the detector settings, click OK to close this window. 4
Figure 5. Detector window. Signal Timing and Settings VISSIM NEMA editor controls signal timing and settings for actuated signalized intersections. If you need add or edit signal timing and settings for an intersection, you need to access the NEMA editor, which is as shown in Figure 6. Figure 6. VISSIM NEMA editor. In order to access the NEMA editor, go to Signal Control in the main menu and click at Edit Controllers in the pull-down menu. The Signal Control window pops up. Click at Edit Parameters in the middle of the right side of the window and the NEMA editor window pops up as shown in Figure 6. The left side of the NEMA editor window 5
contains signal timing parameters and settings. The right side of the NEMA editor window is called phase sequence editor, which contains phase sequence information. Definitions for some fields on the left side of the NEMA editor window as follows: Signal Group (NEMA Phase): signal group number (In VISSIM, signal heads should reference this number and detectors for this movement should have this number. Detector: detector(s) that are assigned to the corresponding phase indicated in the Signal Group (NEMA Phase) field. Amber the yellow clearance interval for a phase Red Clearance the all-red clearance interval for a phase Min Green the minimum amount of green time displayed if a phase starts. Max Green the maximum amount of time that a phase can maintain green once calls on other phases are present. Yellow Lock holds a call for service during next cycle if vehicle detected during the yellow clearance or red time for that phase. Some of the buttons in the phase sequence editor are used as follows: Start Phases/Set Sequence- This button toggles between Start Phases and Set Sequence. If you click to Start Phases, you may click on a phase in the sequence panel to indicate that it is a start phase. The phase will turn red. Note- you must have at least one start phase for the sequence configuration to be valid. If you click Set Sequence, you may drag phases into the rings. Reset Sequence- This resets and unlocks your sequence configuration so that all phases are removed from rings. Note- If you want to define the sequence configuration with rings that are not displayed or you cannot move the phases, try resetting the sequence. 6
STEP 2: Configuring Simulation Output Files Check node settings A node in VISSIM is a area in which evaluation data are collected. Nodes are defined by a cordon line as shown in Figure 7. Node evaluation files provide operational performance measures, such as delay and number of vehicle stops, for intersections that are covered by these nodes. If you need to view an existing node, click at the button Node button indicated in Figure 7. Node Node button Figure 7. Node tools and pops-up window. Once you click at the node button, the node shown in Figure 7 will appear. Double click on this node and the node pop-up window appears as shown in Figure 7. The Node window has two fields including the index number No. and name for this node. Configure node evaluation file Follow the procedures below to configure a node evaluation file. a. Go to Evaluation: in the main menu and click Files in the pull down menu. The Offline Analysis (File) window pops up as shown in Figure 8. 7
Figure 8. VISSIM evaluation output options. b. Check the option Node as shown in Figure 9 and click on the Configuration button adjacent to the Node option. The Node Evaluation Configuration window pops up as shown in Figure 9. c. Select parameters from the field on the right labeled Parameter selection and click on the double arrow to make selected parameters appear in the field on the left labeled Selected parameters. d. Select the following parameters: Movement, Number Veh, and Delay Time and move them over to the Selected parameters field. e. Fill in a file name in the Configuration file field and save the configuration file to a selected location by clicking on the browsing button (labeled ). You should recognize that the node evaluation file will be given the same name as the configuration file and will be saved in the same directory as the configuration file. Click OK to close the Node Evaluation Configuration window. 8
Figure 9. Set up configurations for node evaluation file. f. Click Filter as shown in Figure 8. The Node Evaluation Filter window pops up as shown in Figure 10. g. Select 1 6 th &Deakin in the Passive nodes field and click the double arrow to make it appear in the Active nodes field. The Passive nodes field contains all the nodes available in the VISSIM network. The Active nodes contains all the nodes for which data will be recorded. h. Fill in 0, 900, and 900 separately in fields from, until, and Interval, respectively. These settings define the collection starting time, ending time, and interval sizes, respectively. Click OK and close the Node Evaluation Filter window. 9
Figure 10, Node evaluation options. Configure signal display and detector status evaluation file The signal display and detector status file records time series data of signal indication status, detector actuations, and other variables. To create or edit the configurations of the signal display and detector status file, first select Signal Control in the main menu and click on Edit Controller in the pull-down menu. A window shown as in Figure 11 pops up. Open the tab LDP Config on the right side of the Signal Control window. Double arrow button Figure 11. Signal control window. 10
Two lists are visible in the LDP Config tab. One is the Layout of Columns list and the other is Type (Category). The list Type (Category) contains all available variables that can be added to the list Layout of columns. The Layout of columns is a list of all the variables that will be output to the output file. To add a new column to the list Layout of Columns, select the desired record in the Type (Category) list and select the desired data in the neighboring list if applicable. Then click on the double arrow button to add the selected variable to the Layout of columns list. If you d like to remove a line in the Layout of Columns list, select the line and press Delete key on your keyboard. The two fields at the bottom of the Signal Control window specify names and locations of the configuration file and signal display and detector status files. The configuration file contains currently specified layout of records. The configuration is saved in the file specified in the field Configuration file and the signal display and detector status file is saved in the file specified in the field Recording file. After you re done with configuring signal display and detector status file, click OK to close the Signal Control window. Go to the Offline Analysis window as shown in Figure 8 and check the SC/Det. Record option. After you re done, click OK to close the Offline Analysis (File) window. 11
STEP 3: Run Simulation Before running the simulation, you need to configure simulation parameters, which include simulation time duration, simulation speed, and simulation resolution. Go to Simulation in the main menu and click Parameters in the pull-down menu. The window Simulation Parameters pops up as shown in Figure 12. Fill in 900 in the third field Period. Fill in 10 in the Simulation resolution field. Fill in 1 in the Simulation speed field. Note: simulation speed can be changed during the simulation by pressing certain hotkeys. The minus key - is decreasing speed and the plus key + is increasing speed. In addition, the space bar pauses the simulation. After you re done, click OK to close the Simulation Parameters window. And click on the play button on the toolbar. Figure 12. Simulation parameters window. 12
STEP 4: Simulation Animation Play Back Observe the simulation and answer required questions. NOTE: you may not be able to answer all the questions by just observing the animation. In the next step, you are going to use VISSIM output files to help you answer the required questions. 13
STEP 5: Accessing the Output files Node evaluation file (*.kna) You specified the location and name of the node evaluation file in STEP 2 in item e of the Configure node evaluation file section. Figure 13 shows a typical node evaluation file. The output information that you will want from this file is contained after the row Movement;Veh(All);Delay(All); (see the B bracket in Figure 13). This row identifies three columns, which are Movement, Veh(All), and Delay(All). Data in these columns are defined in the three lines of text above the row of column labels (identified by the A bracket in Figure 13). A B Figure 13 Node Evaluation File. Data in the column Movement, define the from-to direction of the vehicle turning movement. The Veh(All) column contains the count of all vehicles making a given turning movement and the Delay(All) column is the turning movement delay in seconds. Signal display and detector status file (*.ldp) You specified the location and name of the node evaluation file in STEP 2 in the Configure signal display and detector status evaluation file section. Figure 14 shows a typical Signal and Detector Status output file. The output information that you will want from this file is contained in the numbered rows (see Figure 14). 14
The first column of data is the simulation second. The following five columns are the signal displays, or indications, of the signal groups that you selected as part of STEP 2. The remaining columns are data describing detector status. The legends describing what the symbols in these columns mean are given below Figure 14 Signal and Detector Status Output File. Legend for signal group displays or indications: I = Green indication / = Yellow indication. = Red indication Legend for detector status:. = unoccupied = occupied for the whole simulation time step + = occupied for a portion of the simulation time step 15
STEP 6: Examining the Output file data Use the node evaluation (*.kna) and signal display and detector status files (*.ldp) to do the following exercises: 1. Go over the node evaluation file and examine the delay distribution on all phases. Which turning movements are served best (answer in terms of Northbound, Southbound, Eastbound, and Westbound terminology)? Note: Use the signal display and detector status file to complete exercises 2, 3, and 4. 2. Pick two phases on different approaches and find the average green time duration for these two phases during the whole simulation period. 3. Find the maximum detector occupancy time for a phase of your choosing. Detector occupancy time is the sum of simulation time steps during which a detector is continuously occupied by vehicles. 4. The difference between the time when the last vehicle leaves a detector and the time when the green ends for a phase is a measure of how well the intersection is being used. If there is a lot of green time during which no vehicles are using the intersection, while vehicles are waiting on one or more phases then this green time is wasted and is one of the factors in causing delay. Pick two phases on different approaches. Find the maximum wasted green time for each and compare the value between the two phases. 16
STEP 7: Modify Signal Timing and Detector Setup. Change the signal timing and detector setup corresponding to your answers to question e. 17