Note: Zonal data are not required unless user wants to use TRAFFIX™ to perform traffic forecasting for future conditions.
Obtain all relevant information about developments. Select trip generation rates (in and out), split developments into zones according to proximity, land use categories, or need to individually trace impacts of different developments or stages of development. Pick the peak period(s) to be analyzed.
It is possible to use more than one rate at a time (up to eight), and TRAFFIX™ will add them; although, generally only one rate is used at a time. An example of multiple trip rates would be trip generation rates by purpose (home based work, etc.) They would be added together by TRAFFIX™ if different rates were used and were all turned on. Note: each trip rate selected will only be used once for each scenario.
Multiple land uses per zone are allowed, but they must have the same trip distribution and assignment characteristics. If they do not, place them in separate zones. TRAFFIX™ allows positive as well as negative trip rates to be used. Thus, existing land uses that will be modified could be entered as negative rates; and new totals could be entered as positive rates. Note that in lieu of land use amounts, one could substitute total trip generation. Then, the "trip generation rates" would specify inbound and outbound percents of total trips.
Generated trips are calculated as follows for each land use in a zone:
Trips Generated (outbound) = (Land Use Amount) x [Rate1(out)(if selected) + Rate2(out)(if selected) + etc.]
Trips Generated (inbound) = (Land Use Amount) x [Rate1(in)(if selected) + Rate2(in)(if selected) + etc.]
Place the cursor over the desired zone, RightClick, and select the Name option. Enter a name for the zone. Click OK to exit.
Place the cursor over the desired zone, RightClick, and select the Land Use option. Enter the kinds of land uses in the zone and amount description (e.g. Retail GSF, Industrial emps). Click OK to exit.
Place the cursor over the desired zone, RightClick, and select the Trip Generation option to bring up the trip generation rate data entry dialog box. Enter trip generation rate data for each land use within the zone.
Figure 18 Trip Generation Data Entry Dialog Box
Enter numerical amount of land use (e.g. 53.00), up to 999,999.99. (Negative and decimal values are OK.)
Select the trip generation rate from the drop-down field (if more than one is to be used). These must first be defined and selected using the Options|Global|Trip Generation menu options (see Step 2.1).
Enter trip rate in and trip rate out. Check totals immediately below the rates .
If more than one land use type, select the next land use from the land use drop-down field, and enter data for that land use.
When done, click OK to exit to the network editing screen.
Save your data, using the Files pull-down menu or the Save Database button.
If the total trip generation for a zone is already known from a prior traffic analysis, the user can enter that volume in the Amount field and the appropriate in/out percentages in the Rate In and Rate Out fields.
This is where the user tells TRAFFIX™ which zones are to be analyzed and reported. Like intersections, zones can be selected/unselected either as a group or individually. RightClick on the zone tool icons to bring up the options pop-up menu. Choose the Select All For Evaluation or Unselect All For Evaluation options. If a zone is selected, then the square around the zone icon will change color. To select/unselect zones individually, place the mouse cursor over the desired zone, then use the Ctrl-Shift-RightClick keystroke to toggle the selection on or off. (This selection can also be made from the intersection and node pop-up menus.)
If you do not save your work to disk every so often, you could lose it in an involuntary computer or program shutdown. So save the database periodically using Files|Save Database or the "Save" button on the tool bar.
Note: Path data are not required unless user wants to use TRAFFIX™ to perform traffic forecasting for future conditions.
TRAFFIX™ stores its distribution data with the paths, so it is necessary to draw the paths first before specifying the trip distribution (the percent of trips going to each gate from each zone).
Select likely paths (list of nodes) for traffic between each zone and gateway. Multiple paths between each zone and gate pair are allowed by TRAFFIX™. The percent of trips for the multiple paths between one zone and one gate ordinarily should sum to 100 percent. Paths that are identical in both the inbound and outbound directions need only be coded once: with Both specified in the Direction drop down box
Make copies of a sketch or the printout of the network to use to draw the paths from each zone to the various gates. In complicated networks, the path development process can be very taxing and produce frustration. Keeping a physical log of your assumptions and work will be beneficial in the long run. When you return to review your work at a later date, it will be hard to recall what you did, unless you leave yourself some notes!
Beginning users of TRAFFIX™ for Windows often find that, while experimenting with the path drawing function, they have problems drawing paths. Specifically, they get to a point where the program will not allow them to draw another path, or won't permit them to switch to a different editing mode, or won't let them exit the program. This is because the program has detected errors somewhere in the current path, and is displaying a message describing where the problem was found. This feature is intended to guard against the inclusion of invalid paths in the database. If you find yourself in this position, you have two options:
If you are just experimenting and do not really intend to use the current path for analysis work, simply delete the current path. You will then be able to draw a new path, switch to another edit mode, or exit the program without restriction.
If you are preparing a database for an actual analysis project, you should examine the error message to discover what condition is being identified as an error, then correct the condition. If you cannot figure out what is wrong with the path, your last resort is to delete the path and redraw it.
Click the 
button to switch to the Edit Paths mode.
The drop-down fields at the top of the screen will show the selected zone and gate and the currently displayed path between this zone-gate pair. Use the drop-down fields to select the desired zone and gate. Then click the Add Path button and you can begin to draw the actual path.
Specify the percentage of the zone's trips to the subject gate which will use this path. Select whether the path will be for trips into the zone (In), out of the zone (Out) or Both. Note that if you select Both or Out, the program highlights the zone involved in this zone-gate pair and you will begin drawing your path from that point. If you select In, the gate is highlighted and this is where you will begin drawing your path. If you later decide to convert a different path direction type (say from Both to In), TRAFFIX™ will convert the path automatically for you, selecting or unselecting links as required.
Enter the percent of the trips between the selected zone and gate that will use this particular path. The default is 100 percent. The distribution calculation performed by TRAFFIX™ is:
Trips On Path (in) = (Trips Generated [in]) x (Percent Gate) x (Percent Path [in])
The path can then be drawn by using the Shift-Cursor Arrow keystroke combinations to travel along the network from starting point to the destination. As the route is traversed, nodes and links are highlighted to show that they have been included on the path. As the path is drawn, the path status box to the left of the edit window shows the nodes that have been successfully added to the path. (The first number is the node number; the second number is the select set it is associated with. Only one select set will be used up to the point where the path crosses itself, at which point another select set will be used to store the succeeding path items.) When a valid path has been drawn between the zone-gate pair, the Valid? field above the path status box changes from red to green. Until a valid path is selected, this field will be red. If this field is yellow, it indicates that a complete path is drawn, but there is something else wrong (such as an extra item selected, but not connected to the path). If either red or yellow is shown in this field, simply click on the field to find out what error(s) TRAFFIX™ has identified for the path.
An additional method of selecting zones, intersections, links, and gates to form a complete path is done by pointing to the item and using Shift-LeftClick, or by using Shift-LeftClick-Drag to surround one or more items with the marquee box. The item will change color to indicate that it has been selected. This method is useful for making changes to a path which was drawn using the Shift-Arrows method.
Unselect items using Shift-LeftClick, or by using Ctrl-LeftClick-Drag to surround one or more items with the marquee box.
Multiple paths may be drawn between each zone-gate pair. TRAFFIX™ does not require that the sum of the percents for all paths equal 100 percent. The total percents for all paths for the selected zone-gate pair are displayed in the Edit Paths tool bar for easy reference.
Check the total percentage for the selected zone-gate pair. Make sure they equal 100 percent for each direction (unless you have a specific reason for using more or less than 100 percent). If necessary, use the drop-down fields to review all paths between the selected zone-gate pair. Edit the percent or direction of the path as needed.
Once satisfied with the path, go on to the next path for the same zone-gate pair by clicking the Add Path button. To go on to another zone-gate pair, first change the zone and gate drop down boxes to select the desired zone-gate pair, then click Add Path. Note that a path will not be accepted by TRAFFIX™ if there are errors in it. Corrections have to be made (or the erroneous path deleted) before you can go on to the next path, or before you can exit the Edit Paths mode.
The Duplicate Path button creates a copy of the current path, which is useful if two slightly different paths are needed to split the trips from the selected zone to the selected gate. The copy of the original path can be edited to form the second path.
The Delete Path button will delete the currently displayed path.
The AUTO PATH button will automatically determine and select the shortest path for you, based on either distance or travel time (with or without intersection delay). Note: the user may also have TRAFFIX draw paths automatically to/from all zone - gate pairs by using the Tools/Autopath feature.
When multiple paths have been defined for a zone-gate pair, use the F3 key to switch to the previous path and use the F4 key to switch to the next path.
Use the F5 key to switch to the previous gate and use the F6 key to switch to the next gate. Use the F7 key to switch to the previous zone and use the F8 key to switch to the next zone.
When done with paths, click on the 
button to switch to the Edit Network mode.
Note: A path must have at least three nodes including a gate and/or zone nodes for TRAFFIX™ to determine which turning movement is to be assigned the path's trips.
Estimate the percent of trips leaving the study area by each gate based on the existing traffic volumes at gates, regional model data, the U.S. Census data or some other source. The sum of these gate percentages normally equals 100 percent. TRAFFIX™ will generate a warning message if the sum is not 100, but will accept such sums. The user may have a good reason for sums other than 100 percent, e.g., the sum may not include internal trips. TRAFFIX™ permits designating multiple distribution rates (up to eight) for the zone system. Generally, these are used for different time periods but they may have other uses as well. However, unlike trip generation rates, only one distribution rate can be active at a time.
One or more trip distribution percentage sets must be defined before you can enter the actual zone-to-gate percentages. Use Options Global Trip Distribution Rates|Edit Trip Distribution Rates to define trip distribution percentages. Enter a name for each distribution set for which you want to enter data.
Then choose Options|Global|Trip Distribution Rates|Select Trip Distribution Rate to select the active rate for the current scenario.
To enter trip distribution percentages between a zone and the various gates, point to the zone and use RightClick to bring up the zone dialog box. Choose Trip Distribution to bring up a data entry dialog box. See Figure 20 Trip Distribution Data Entry Dialog Box below.
Use the drop-down fields to select the gate and trip distribution set, then enter the percentage of trips from the subject zone to the displayed gate in the distribution drop-down field.
Continue this process for all gates, checking the total percentage entered for all gates as displayed in the dialog box. TRAFFIX™ allows the total to vary from 100 percent, if desired. Note: the user may also have TRAFFIX automatically define path percentages (100% divided equally among all paths) for each zone - gate pair for which the user has not defined these percentages by checking the "Auto Allocate Paths?" box in Options/Global Data/Parameters and running the forecast.
Click OK to exit, and repeat Steps 3 through 5 for the other zones in the network.
Figure 20 Trip Distribution Data Entry Dialog Box
Trip Generation and Distribution Screens
The following paragraphs provide useful information on trip generation and trip distribution screens. All users should read this section before moving on to running the forecast analysis.
TRAFFIX™ only allows the selection of one trip distribution percentage set at a time for each scenario. When one percentage set is turned on, all other sets will automatically be switched to off. However, TRAFFIX™ does allow the user to turn on more than one trip generation rate set at a time. Conditions where a user might wish to use more than one trip generation rate at the same time include the following:
Phasing of New Developments. Rate 1 would be for Phase 1 of a project and Rate 2 for incremental trip generation of Phase 2. Turning both rates on would generate total trips for the project. Without the use of a second rate, the user would have to add an additional zone.
Major Changes to an Existing Development. Rate 1 would be for total new trips, and Rate 2 would be for existing trips and would have a negative sign. When both rates were turned on, the existing trips would be subtracted, and total trips for the new development would be added.
Forecasting Daily Trips using Peak and Off-peak Totals. The use of multiple rates can be used to generate daily trips when peak and off-peak totals have been provided. Note: No level of service calculations can be made with daily trip totals using TRAFFIX™.
These situations could also be accommodated by the use of additional zones, but the use of multiple trip generation rates is more efficient. When using more than one generation rate, remember that the rates that have been turned on apply to all zones that have been selected. Rates cannot be turned on for one zone and off for other zones.
To run the forecast analysis module and produce an output file with the desired reports, choose Tools|Evaluate, and the select either Forecast to run the forecast for the current scenario, or Forecast All to run the forecast for all scenarios in the database at the same time. Alternatively, click either the Run Scenario or Run All Scenarios hot buttons on the main screen.
It is recommended that the database file be saved before a forecast is made to ensure that no data are lost if for some reason the program is halted during the forecasting process.
Before running TRAFFIX™ with zones turned on (selected for analysis), check to see that the base year LOS values are correct. Run TRAFFIX™ for base conditions, and check the results against existing field conditions. This check allows the user to verify that everything in the network is correct relative to node information, the method of calculation, etc.
Check the name of the Output file to make sure that it is correct (Options|Global|Output File). If the output file already exists, TRAFFIX™ will overwrite it. The name should include a suffix as well as a prefix ("out" is recommended but any suffix could be used).
Make sure the desired intersections and zones have been selected for analysis.
Choose Tools|Evaluate|Forecast (or Forecast All). Various informational messages will flash by on the screen during the forecasting process. TRAFFIX™ is writing both the output file and a log file (which contains information, warning, and error messages for later review).
Click the View Report button to review the output reports. Use the arrow keys, page up, page down, or the mouse to move the file within the window.
Select View Log and review it for unforeseen error messages.
It is strongly recommended that the log files be reviewed after every run to check for unforeseen problems with the analysis and in many cases should be printed out. For some methods, TRAFFIX™ will undertake calculations even when boundary conditions established in manuals have been exceeded. It is expected that the user will check the results in these cases to ensure that they are reasonable. It would be too restrictive not to calculate answers every time boundary conditions are exceeded.
If satisfied with the results, you can print the results by clicking the Print button. You can also print the results later using the Tools|View File option. After exiting TRAFFIX™, you may use the DOS command "copy TRAFFIX.out prn (lpt1, etc.)" or import the file into a word processor. When using a word processor to format output files, remember to choose non-proportional fonts, such as Line Printer or Courier, or Courier New, so that column formats will be retained. Tip: Select 6 pt Courier New, landscape orientation, two column layout, and replace all manual page breaks with column breaks to convert the TRAFFIX™ one-per-page reports to a two-per-page format which greatly reduces the size of the output file for inclusion in technical appendices. A simple macro can be created within your word processor program to automate this process. Alternatively, many newer printers have the option to print 2 sheets to a page in their Properties settings.
Review the warning messages that TRAFFIX™ generates. Messages are designed to identify data combinations that are inconsistent or illogical and create results that should be reviewed.
Check the trip generation report to make sure the total inbound and outbound trips are adding the desired number of vehicle trips in and out of a particular lad-use /zone.
Check the trip distribution report to make sure that all trips between zones and gates have been allocated. TRAFFIX™ expects, but does not require that the distribution equal 100%. If this total does not equal 100%, TRAFFIX™ will make note of this in the Log file.
Check the link volumes report to make sure that the volumes on links connecting each zone to the network equal the number of inbound and outbound trips generated. The link report will include all nodes at which any data have been entered, unless the "Report Only Selected Intersections" option has been chosen in the Options|Global|Parameters dialog box.
Check that Outbound trips = Volume "In" to the intersection.
Check that Inbound trips = Volume "Out" from the intersection.
Both the output and input reports can be used to check for data entry and analysis errors. First check the trip generation and distribution reports against data sheets. Check the link volume reports to ensure that paths have been entered correctly. Edit Path mode can be used to check the paths in those instances where it appears an error has occurred. In addition, the "movement by zone" report can provide important information about how the model is assigning trips from each of the traffic zones. Also, the impact fee analysis can be used to help spot "skipped" intersections and other errors in the paths. Report the level of service calculation details to verify the correct coding of geometry and other factors used in the LOS analysis. Finally, compare LOS results for the base case against field observations.
After you have successfully completed a forecast or base year run of TRAFFIX™, you should save your data if you did not do so before. In fact, you should save and save often when you use TRAFFIX™ or any program used to produce work products. TRAFFIX™ holds the current data for all of the elements in memory. A loss of power to the computer will result in the loss of any data that has not yet been saved.
When you change intersection data while in the LOS Mitigate screen, TRAFFIX™ will not update the database to include the changes unless the user exits by clicking OK. On the other hand, if you click Cancel, the original data are retained. In either case, the data is not saved to disk until the File|Save menu option or button is used.
TRAFFIX™ offers an interactive screen called "LOS Mitigate" for testing the level of service impacts of different lane geometry and signal timing configurations. See Figure 21. The mitigation measures determined from the screen can then be saved, labeled, and priced for use in the impact fee analysis. An impact fee report can then be requested which identifies the traffic contributed by each development zone to each intersection requiring mitigation.
To identify critical intersections in the network, switch to the Edit Network mode (if not already in that mode). Place the mouse cursor on any intersection (signal, stop, unsignalized) icon and "RightClick." From the pop-up menu select Display Index and Base LOS (or for future conditions Display Index and Future LOS). The intersections on your network will now have the appropriate level of service designation displayed next to their index numbers. Green is used for levels A - C, yellow for levels D, and E, and red for level F. If you select Display Index and Future LOS, the level of service will be displayed with a "*" to indicate that the future conditions are being displayed. Note: this mode of operation significantly slows the network display process, and should be used with that in mind.
Figure 21 Intersection Mitigation Screen
Place the mouse cursor over the desired intersection. RightClick and choose LOS Mitigate get the LOS Mitigation screen. Select the base or future volume alternatives from the drop-down field in the lower left corner of this screen.
Change the number of lanes and signal timing until you have achieved the desired results. This screen will let you code conflicting and illogical lane geometry and signal timing, so be sure to observe the error count in the lower right corner. Click View Log to review the error messages. Make sure that you have either corrected all the errors or at least accepted the warnings, before deciding to accept the level of service results.
You may switch calculation methods in the drop-down field in the upper left corner. The intersection control method can also be changed by clicking the intersection type icons at the bottom of the screen. This changes the analysis method on the LOS Mitigate screen and changes the node icon on the network display. Note that some data may be lost in the conversion of control method, so don't click OK until you are sure you want to keep the changes you have made. This change will take effect in all scenarios within the database. If you don't want to lose your original control settings, make the changes and then save the database with a new file name.
Use the drop-down fields at the top of the screen to enter a description and cost of the mitigation measures for use in the impact fee analysis.
To save the changes you have made, exit this screen by clicking the OK button. Click the Cancel button to exit without saving the changes. Click the Reset button in the lower left corner to reset the settings to those of the last save.
TRAFFIX™ offers two methods for calculating impact fees. One method is based solely on trip generation. The other method utilizes the actual number of trips each project adds to each intersection.
To calculate impact fees based on trip generation turn on the trip generation for all the desired development project zones by selecting them for analysis (to select all zones, LeftClick on the zone tool icon, then choose Select All For Evaluation). The Trip Generation Report shows the number of trips in and out generated by each development and the percent that these trips represent of the total generated by all the development zones.
For a more detailed impact fee calculation, providing a closer "nexus" between the development impacts and the fees, the special Impact Fee Report generated by TRAFFIX™ shows the number of trips from each development zone, which are added to each critical intersection.
The existing base volumes can be included in the Impact Fee report by selecting the Impact Fee (Base) Report, under the Options|Global|Reports menu. Otherwise, base volumes can be excluded from the fee calculation by selecting the Impact Fee Report (although base volumes are indeed included in the level of service analysis).
The user must enter the cost of the mitigation improvements for the intersection (move your cursor to the intersection, RightClick, select Improvements, then enter a description and a cost in the dialog box). See Figure 22. TRAFFIX™ will then calculate the proportion of this cost attributable to each development zone based on their relative contribution to the total (or incremental) number of trips at the intersection.
Figure 22 Improvement Data Entry Dialog Box
The Impact Fee Report must necessarily round off the dollar amounts. The row and column totals however are based on the non-rounded values. Consequently the individual table entries may not add to the row and column totals. The row and column totals are thus more accurate than the individual entries in the table.
If percentage impact information is desired, code the mitigation improvement costs as $1.000 million. The results shown in the report's table for dollars can then be interpreted as proportions or percentages.
