The Global Data menu can be accessed from the Options menu or by pointing to a blank area of the network window and using Right Click to bring up the Global Data pop-up menu. Enter the necessary global data including:
The user has the option of selecting any combination of reports. All reports are selected as the default choice, but generally the user will select only those reports relevant to the analysis where the appropriate data has been entered. The "future" reports should be used only when one or more zones have been selected to generate trips. The "LOS Compute" report is the standard report for level of service analysis. The "LOS Detail" reports apply only to the HCM Operations Method for signalized intersections. The "Level of Service Summary" report will include a tabular, sortable summary of both intersection and arterial analysis. The "Movements by Zone" report includes turning movements added to each of the study intersections by each of the traffic zones. The "Impact Fee" reports should be unchecked unless mitigation cost information has been entered. The "Queue" reports will show the queue length per lane by lane group (L, T, R) for all twelve approach movments in either number of cars or distance, based upon the user entry of "Queue length by Cars" or "Queue Length by Distance" in the Options/Global Data/Parameters input screen. The "Threshold" reports will report a summary of the LOS, delay and V/C for all movements meeting or exceeding the threshold criteria entered in the Options/Global Data/Parameters screen.
The OK All Scenarios button allows the user to apply the current report selection set to all of the defined scenarios in the current TFX dataset.
The Compare Scenario dialog (under the Tools menu) produces several reports that compare the LOS results of up to four user specified scenarios. The scenarios to be included are specified in the Compare Scenario Parameters dialog box, which is accessed from Options|Global Data menu. See Figure 5.
The user can request that a LOS Computation Report for each intersection in each scenario be produced along with the scenario comparison reports. These are the same reports that are produced by the Evaluate run when the LOS Compute reports and the LOS Detail reports are selected in the Reports dialog box. To request these reports during the Compare Scenario run, check the appropriate boxes in the Compare Scenario Parameters dialog box.
The user can also request that TRAFFIX™ output a standard text based tabular report, and/or a Graphic/RTF (rich text format) summary that includes a simple graphic representation of the intersection geometry. This RTF file (like all of the TRAFFIX™) output files can be manipulated with a simple external text editor program or a more robust word processing program.
Figure 5 Compare Scenario Dialog Box
The Titles and Parameters dialog screens are two of the most important data entry screens in preparing a TRAFFIX™ database. Controlled by the Command control in the Edit Scenario Dialog Box (see Figure 33 Edit Scenario Dialog Box). Unless modified and specified for each scenario, the data on these screens are used globally throughout the database. The titles for each scenario's reports are entered on one screen, and several key parameters and settings are specified on the other screen.
On the Titles Screen, type in the scenario's report titles (up to three lines). See Figure 6. Trip generation and trip distribution titles are optional. Leave the Volume PassBy Name field blank for now. The comment lines will not appear in any report but can be used to provide documentation comments on the analysis that will be helpful to the user viewing the TRAFFIX™ file at a future date.
On the Parameters Screen, specify for the current scenario the key global parameters to be used in the analysis (See Figure 7 Parameters and Intersection Parameters Dialog Screen). Then select the default level of service calculation method for signalized intersections, unsignalized intersections, 4-way stop intersections, and roundabout intersections. Specify whether all intersections are to be included in the volume output reports, or just those that have been selected for LOS analysis. Choose whether G/C ratios or Green times are to be used in the output reports.
Choose whether or not the LOS grade modifiers (+ and -) are to be used with the LOS letters in reports and on screen. To avoid accidental changes to the network layout after it is created, the user may "lock" the network features in place with the "Lock Network?" field (which applies to all scenarios). Select the queue calculation methodology and confirm or modify the default average vehicle length used in the queue calculation.
TRAFFIX™ can utilize "metric" or "customary" (imperial) units of measurement. These distances are utilized in the vehicle length calculations as well as the lane-width saturation flow factors.
Select the peak hour traffic signal warrants to be analyzed, by choosing the peak hour delay warrant and/or the peak hour volume warrant. For the peak hour volume warrant, select "urban" or "rural or over 40 mph 85th percentile speed on major street."
Specify Level of Service parameters for the global LOS analysis method to be used for the current scenario. Normally the default values are accepted; however, the defaults can easily be over-ridden by specifying new global values on this dialog screen. New saturation flows can be entered either as adjustment factors to modify the default values at the top of the dialog box, or as new per-lane rates (which TRAFFIX™ will then convert to equivalent adjustment factors).
TRAFFIX™ allows the user to create an accurately scaled network. Combined with the ability to import a scale raster or vector image into the network background, this function allows TRAFFIX™ to more accurately calculate link lengths based on the users placement of intersection nodes.
Figure 7 Parameters and Intersection Parameters Dialog Screens
Specify for the desired analysis method(s) the delay type and queue calculation type, or choose "Use Global Method" to set the queue length calculation based on the selection entered in the Options/Global Data/Parameters window.
Specify whether delay calculations are to be produced for the various LOS analysis methods to be used in the current scenario. This determines whether an average delay/vehicle is included in the output reports. Some LOS methodologies do not use this parameter. Normally the default values are accepted. The option to use the average critical delay for the critical movements, instead of the average delay for all movements, is also provided.
Figure 8 Compute Delay Dialog Box
Define land use names and trip generation rates globally. First enter the name(s) of the land use(s) for which global trip generation rates are desired. Then enter the rates for the land use(s) for each trip generation rate set (defined by steps below). This information can also be entered by reading a TRAFFIX™ XML file, as described in Chapter 11.
Define one (or up to eight) trip generation rates, then select by selecting "Yes" the active trip generation rate(s) for the current scenario. More than one set can be selected for a given scenario; however, each rate will be used only once in a given scenario. At least one must be selected. The ordering of the scenarios is not important in the dialog box.
Figure 9 Select Trip Generation Rate Dialog Box
Define one set (or up to eight sets) of trip distribution percentages, select the active trip distribution percentage set for the current scenario. TRAFFIX™ allows the use of only one trip distribution rate at a time for each scenario. One must be selected.
Figure 10 Select Trip Distribution Percentages Dialog Box Output File Name
Specify the path and output file name for the current scenario, or accept the default name (TRAFFIX.out). Also specify the output file names for the Compare Scenario report (default: TCOMPARE.OUT, SUMMARY.RTF,DETAIL.RTF, etc.) Users may wish to send the output to a location other than the default working directory.
Figure 11 Output File Dialog Box
Specify (the destination path if other than the current working default directory) log file name for the current scenario, or accept the default name (TRAFFIX.log). Also specify the log file name for the Compare Scenario log (default: TCOMPARE.LOG). The log file records the actions of TRAFFIX™ during an evaluation and can help identify coding errors and bugs that prevent full evaluations.
It is often desirable to analyze more than one scenario, e.g., morning peak hour conditions and afternoon peak hour conditions. Typically, only some of the data will change from one such scenario to the next. For example, the base traffic volumes will be different, the trip generation will be different, and the trip distribution might be different. Click the Edit Scenarios button, or choose Options Global|Scenario, to define alternate analysis scenarios, using multiple data sets. Figure 13 shows the Scenarios dialog screen.
First specify the desired scenario names. Then specify the names of alternate data sets that will be used. Then select which data sets will be used for each scenario. The scenario shown in the Scenario drop-down box (at the top of this dialog screen) is the scenario being edited. (Tip: although scenario names can be as long as you want, use short scenario names because the space allotted for these on the output reports is limited. Data set names are not used in the same way, so they can be any desired length.)
For example, to define separate scenarios for AM and PM analysis cases, first choose Options|Global Scenario|Edit Scenarios. Then click the Scenario button and enter the two different scenario names. Then click the respective data set buttons to define a separate name for every type of data set that will vary from scenario to scenario. For instance, make sure that you name an AM and PM data set for at least Volumes, Trip Generation, and Trip Distribution (if they will differ). You might also want to name separate AM and PM Mitigated scenarios and separate existing and mitigated Geometry data sets. If you want different titles and output files for each scenario, you will need to name separate Command data sets for each scenario.
With the AM peak hour scenario name in the Scenario drop-down box, use the arrows on the respective drop-down boxes to show and select the data sets that will be associated with this scenario. Then do the same with the PM peak hour scenario name in the Scenario drop-down box. Then exit the Edit Scenarios dialog box.
Note that if you have already entered data before you define scenarios, all of the data are in the Default scenarios and data set areas. In defining scenarios, the first scenario name you enter will become the new name of the Default scenario. Similarly, the first name you enter for each data set type will become the new name of the Default data set for that data type.
Figure 13 Scenarios Dialog Box
This feature allows the user to specify different path percentages for different scenarios. Within the TRAFFIX™ program there is one master set of paths available to all scenarios. By defining several paths and assigning varying percentages to each path according to the particular scenario, the user can effectively manage the paths for each scenario.
Because TRAFFIX™ maintains a single list of paths, if a user deletes a path in one scenario, it will be deleted and unavailable for all scenarios. If desired, a path can be effectively turned off for a particular scenario (as defined in the Edit Scenarios|Path input) by giving that path a zero percentage.
These buttons and drop-down boxes do not create and select trip generation rates and trip distribution percentages. But if the user wants to have different generation rates and different distribution percentages for different scenarios, then separate data sets must be defined here and associated with each scenario. This also allows for different trip generation and trip distribution titles, which are entered on the Options|Global|Titles dialog box. To create and select generation and distribution rates for a given scenario, use the Options|Global|Trip Generation Rates/Percentages dialog boxes. If you don't define separate data sets for each scenario, then the last generation rate or distribution percentage set to be selected (regardless of which scenario is active) will be used for all scenarios.
This feature allows the user to define different arterial analysis route sets for evaluation in each scenario. The route button and drop-down box does not create routes; however if the user wants to have different routes for different scenarios, separate data sets must be named here and associated with each scenario. The Routes scenario feature allows the user to specify different routes for arterial analysis in each scenario. All routes are available to all scenarios; however, by changing a route's "Evaluate" field (Yes/No) in the Edit Routes mode, routes can be included or excluded from evaluation in the current scenario.
This feature allows the user to name different impact fee data sets for each scenario. In this way there can be different mitigation measures and costs, and different impact fee calculations performed for each scenario.
This feature affects TRAFFIX™ related software and run settings including Titles, Global LOS Methods, Calc. Saturation Adjustment, Report Only Selected Intersections, Lock Network, and Comment Lines (on the Options|Global Data|Titles/Parameters dialog screens); Output File Name, Log File Name, Reports, Compute Delay (on the Options|Global Data menu).
For example, if separate command data sets are named, each scenario can also have its own Title, Output File name and Log File name if the user desires (these are accessed from the Options|Global Data menu).
This feature affects traffic engineering analysis factors and parameters, including Vol. Adj., Growth Factor (G.F.), Delay Adj., Delay Parameters, Max. Cycle, Population, Metric Units, G/C vs. Green time, and LOS Grade Modifier (on the Options| Global Data | Parameters, Intersection Parameters & Titles dialog screens), and LOS Parameters (on the Options|Global Data menu), and local intersection LOS Method (from the intersection pop-up menu via Geometry|Signal Timing). If separate configuration data sets are named, each scenario can have different values for these items. One of the more common applications of a specialized configuration file would be the creation of a future traffic scenario that would utilize a growth factor to increase all existing turning count volumes by a set rate. Figure 14 illustrates an Intersection Parameters dialog box set to increase all the observed Base volumes by 15%. Note that this growth factor will affect Base Volumes in both the Base Volume Alternative and the Future Volume Alternative.
Figure 14 Example of an Intersection Parameters Dialog Box with a 15% Growth rate
The active scenario is that shown in the Scenario drop-down box in the upper left corner of the toolbar area, above the network window in Edit Network mode. Any changes made in the Network, Paths, or Routes edit modes will be associated with this active scenario. The active scenario name also appears in the title bar of the network window and is printed on each page of the forecast output reports.
To continue this scenario definition example, return to Edit Network mode and make the AM scenario the active scenario in the Scenario drop-down box. Use the Network, Paths, and Routes edit modes and follow the steps outlined in 3.1 OVERVIEW OF THE PROCESS to enter all of the data needed for the AM analysis case. This would include (but not be limited to) the network features, the intersection geometry, the AM volumes, the AM trip generation rates, the AM trip distribution percentages, and the paths. Next, make the PM scenario the active scenario in the Scenario drop-down box, and repeat the above steps for the data items that change for this scenario. Remember that unless separate data set names have been created, both scenarios will have the same data for a given data set type (e.g., geometry, configuration, etc.), and these will automatically be named Default (e.g., Default Geometry, Default Configuration, etc.).
Whenever a scenario is made active by being selected in the Scenario drop-down box in the Network Edit mode, all of its associated data sets become active, and any changes made affect only that scenario, unless the data sets involved in the changes are shared by other scenarios.
TRAFFIX™ for Windows uses only one network for all of the scenarios in the database. Therefore, any changes made to the network (adding/deleting intersections, links, gates, zones) will apply to all scenarios. This means that a given intersection cannot be unsignalized in one scenario and signalized in another scenario. If you change it from unsignalized to signalized, the change will take effect in all scenarios. If your analysis problems require alternate networks, you should create separate databases, each with a different network.
