Note: The Roadway Optimizer is also covered in the Street Lighting course in the AGi32 Online Learning collection.

Files referenced:

Tutorial-RdwyOptimizer.AGI (completed file)

Time Estimate: 1 hour


Roadway Optimizer is a handy tool within AGi32 that provides a quick answer to the question, what should the pole spacing be? You may ask Roadway Optimizer to optimize based on design criteria that you set and with a grid and observer defined by any of several roadway standards, including IES, CIE, British, Australian, and New Zealand. You may select from several types of pole layouts (opposite, staggered, median mounted, etc.) as well as several pavement types, as defined by the roadway standards. You may compare up to five different layouts and then print the results or export them to Model Mode.

Roadway Optimizer allows you to optimize your pole layout based on metrics associated with roadway lighting applications in a straight segment of roadway. The optimization process is based on the user’s selection of the roadway standard to which the model will be designed. AGi32 includes default input parameters for grid placement and point spacing based on five roadway standards in use around the world:

  • The IES method uses the algorithms in IESNA RP-8-14
  • The CIE method uses the algorithms in CIE 140-2000
  • The Australia and New Zealand methods use the algorithms in Australia/New Zealand Standard 1158.2-2005
  • The BSEN method uses the algorithms in the 13201-3.2003 document
  • The ABNT method uses the algorithms in the Brazilian document NBR5101-2012

For more details on these standards and their metrics, open the Help topic called Roadway Standard - Calculation Metrics. In this tutorial, we will use IES RP-8-14.

Roadway Optimizer utilizes a two-dimensional typical section environment as defined in the specific roadway standard. These typical environments do not consider surfaces other than the roadway as defined in the standard. 

Problem Statement

Use Roadway Optimizer to determine the optimum pole spacing for two different luminaires, following IES RP-8-14 criteria. Compare the results and decide which is preferred. Print the results if desired, and then export the preferred layout to Model Mode. Use Project Manager to change which calculated metric is displayed in Model Mode.

Tutorial Summary

Step 1 – Define two luminaires

Step 2 – Enter the road specifics into Roadway Optimizer

Step 3 – Input design criteria and calculate.

Step 4 – Do the same for the second luminaire

Step 5 – A look at Precision Settings

Step 6 – Comparison tab: decide which luminaire to use; Export results

Step 7 – Calculate in Model Mode

Step 8 – Project Manager: Notice what was calculated, what is displayed. Change the display.


Step 1 – Define two luminaires

As Roadway Optimizer requires at least one defined luminaire, our first step is to define a luminaire to be used within the model. The luminaire definition process assigns a variety of attributes to a photometric file, such as light loss factor (LLF) and symbol associations. Once defined, the luminaire is available in this configuration as needed in this job file.

In Model Mode, click on the Define button in the Luminaire Toolkit to access the Define Luminaire dialog.

The Define Luminaire button in the Luminaire Toolkit (Menu: Add - Luminaire - Define)

For this tutorial, we will select the photometric files from the demonstration database that is included with AGi32. It’s titled “Z-Lux Sample Instabase” and can be found within AGi32’s Photometric Instabase.

Access the Photometric Instabase by clicking on the Instabase button in the Define Luminaire dialog.

When the Instabase In The Cloud (IITC) dialog opens, the luminaire photometric data supplied with AGi32 is available for download. Our first step will be to set up a User Profile. This is normally option, but it has the advantage that any Favorites or other settings that the user enables will be available from any computer by simply signing in. 

Click on the User Profile tab at the top of the dialog.

Click on the link to Sign In or Create a User Profile.

In the lower half of the dialog, create a new User Profile: Enter your first and last name, your email address, a Username (anything you like), and a password that you can remember. Then click OK.

For this tutorial, we will be using luminaires from a "pretend" manufacturer called Z-Lux. The luminaires and their photometric data are not real and are only accessible by entering an Access Code. This is to prevent them from being used in real lighting designs!

On the right-hand side of the dialog, enter this Access Code: pretend. Then click on the "save" icon to the right.

Now you should see this:

Go to the View/Search tab.

At the top of the dialog, click on the Select Manufacturers link.

Scroll to the bottom of the dialog and select Z-Lux Sample Instabase (22) (private). Then click OK (bottom of dialog):

The Instabase User Guide will open. It has tips for those who are new to IITC. Close it by clicking on the X in the upper-right corner. (Be careful not to close the IITC dialog!)

Now we are in the main part of the IITC dialog, with the Z-Lux Sample Instabase displayed. We may now either perform a Search (using the fields on the left side of the dialog) for luminaires that meet specific criteria, or simply select the luminaire(s) that we wish to download for our project. We will do the latter.

NOTE: If you have been in IITC and downloaded luminaires already, they will be pre-selected. You will want to first click on the Unselect All button at the bottom of the dialog to avoid downloading them again.

  1. Click on the “-” next to the ZL-Indoor node to collapse it. (Collapsing this node saves a bit of scrolling.)
  2. Under the ZL-Outdoor node, in the ZL-Area group, select the zlroad2.ies luminaire. You will see its characteristics shown to the right.
  3. Also select the zlroad3.ies luminaire.
  4. At the bottom of the dialog, click Download.

The zlroad2 luminaire has its own symbol, but the zlroad3 luminaire does not, so the Smart Symbols dialog opens.

Begin by selecting Pole as the mounting type. Next, click on theBox Down symbol to select it. Then click OK.

Both of our selected files are now in the Defined Luminaires section at the top of the Define Luminaire dialog. We need to make a few changes to our two luminaires, however, to make them appropriate for our project.

Select the zlroad2 luminaire. The default Label is the IES filename, which we will accept.

For the Description, enter: 400W MH, Type III.

This will be a pole-mounted luminaire, so select Pole and Dynamic, Attach To Z=0.

Enter an Arm Length of 3 (feet).

Click on the LLFs Specify button.

In the dialog that follows, enter 0.7 in the LLD cell, 0.8 in the LDD cell, and 0.95 in the BF cell. You can see that we have a total light loss factor of 0.532 for this luminaire.

Click OK to return to the Define Luminaire dialog.

Click on the Add/Redefine button to keep all of these changes.

Next, select the zlroad3 luminaire.

Make these changes:

  • Description: 310W HPS, Type II
  • Arm Length: 3
  • Specify LLFs: LLD = 0.8, LDD = 0.8, BF = 0.95

Click the Add/Redefine button.

Click on the Close button to exit the Define Luminaire dialog and return to Model Mode.

Step 2 – Enter the road specifics into Roadway Optimizer

Now that we have defined our luminaires, we can use Roadway Optimizer to determine the optimal pole spacing that would be required for each type in order to achieve our lighting design criteria.

Click on the down arrow next to the Design Tools button and select Roadway Optimizer.

For the purposes of this tutorial, we will assume the type of road, type of pavement, and other particulars that you would normally get from your project leader. We will also assume that we have obtained the number of lanes, lane width, etc. from a drawing.

Assumption for this project: Collector Road with a low potential for pedestrian conflict

Enter the additional assumptions below in Roadway Optimizer.

  1. We will follow the IES Recommended Practice for Roadway Lighting, RP-8-2000
  2. For the Roadway Layout, select Two Rows, Staggered, With Median from the drop-down list.
  3. 2 lanes in each direction. 
  4. Note that RP-8-00 defines the design criteria for the driver's side of the road only. Some other standards, such as British standard BSEN 13201-3.2003, define criteria for both sides of the road. In that case, you would specify the number of lanes on the opposite side as well.
  5. Roadway width = 24 feet; median width = 4 feet
  6. Pavement type: R1 (defined in RP-8-00)
  7. We will use the zlroad2 luminaire, the default selection. This is the 400W metal halide.
  8. Enter a mounting height (MH) of 30 feet.

In the next step, we will enter the design criteria that we want to achieve.

Step 3 - Input design criteria and calculate.

RP-8-14's Luminance Method tells us that a Collector road with low pedestrian conflict has the following design criteria:

  • Average Luminance = 0.4 cd/sq.meter
  • Uniformity Ratio, Avg/Min (Lavg/Lmin) = 4.0
  • Uniformity Ratio, Max/Min (Lmax/Lmin) = 8.0
  • Veiling Luminance Ratio (LVmax/Lavg) = 0.4

In the Roadway Optimizer dialog, place a check mark next to these criteria and enter the values:

  • Average Luminance: 0.4
  • Avg/Min Lum Ratio: 4
  • MaxLvRatio: 0.4
  • Max/Min Lum Ratio: 8

Then click the Calculate button (main toolbar).

The display shows the point-by-point luminance values.

The results window shows the statistics achieved. Several metrics were calculated, but only the Roadway Luminance point-by-point is displayed. Click once on any heading will cause it to be displayed in the graphic.

All four of our criteria were achieved. They are shown in bold black. (Scroll down to see MaxLvRatio.) Any criteria that we had not achieved would be displayed in bold red.

The calculated pole spacing to achieve these results is also shown: 404 feet. (Note: This is the spacing on one side of the road.)

We can also see that Roadway Optimizer used 15 iterations to achieve these results. Let's see what that means.

Roadway Optimizer will try to achieve all the criteria that you specify, starting at the top of the list and working down. This is an iterative process. Since for any given lighting design, it may or may not be able to achieve all of the criteria, it will prioritize from top to bottom. Therefore, the Average Luminance, if it's checked, is given highest priority in the optimization process.

Click on the gray Settings button on the Main Toolbar.

This dialog shows the Optimizer Settings. These govern the way that Roadway Optimizer approaches the optimization process, including the precision settings (how close is close enough) and the number of iterations.

Keep this possibility for adjustment in mind; if you are not able to achieve your desired criteria in the number of iterations set here (default = 20), you may increase this value and try again. Of course, the more iterations Roadway Optimizer uses to reach the design criteria, the longer the optimization process will take. However, it will stop if it reaches the criteria before using all the iterations. It will also stop if it determines that it cannot reach all the criteria as specified.

You may also alter the Precision Settings, as well as the value for Round Spacing To Nearest 1 ft. If you are working in Meters, this will be to the nearest 1 meter, which might not be precise enough to achieve your desired criteria.

Notice that all of the Calculation Metrics are checked by default. The checkmark means that any of these that are calculated (depending on the standard chosen) will be displayed on the Comparison tab, and they will also be included in printed results if Roadway Optimizer's Print option is selected.

Close the Settings dialog. We won't make any changes at this time.

You can zoom in to see the values better; use the Zoombutton in the graphics display window. You may also use the other navigation buttons at the top of the display to view the grid and layout from different perspectives.

Click on the Toggle Display Mode button at the top of the dialog to make the display larger. You may click on it again when you are ready to return to the normal setting.

Notice the arrows to the left of the grid. They indicate the direction of traffic flow.

If you were to zoom out further, you would see the Observer positions. The default location for the Observers is 83.07 meters (about 272.5') before the grid.

Step 4 – Do the same for the second luminaire

Next, we will do the same for the HPS luminaire and then compare the results of the two luminaire types: spacing criteria met, etc.

Select Layout 2 at the top of the dialog. This will transfer all settings to Layout 2.

Next, change the luminaire type to zlroad3. this is the HPS luminaire.

Do this for Row 1 and Row 2.

Keep all other settings the same.

Click the Calculate button.

This time, Roadway Optimizer was not able to meet all four of the criteria. It stopped after 16 iterations without having met the Avg/Min Lum Ratio, which is displayed in red bold. It determined that additional iterations would not help, so it stopped. The results are displayed: 209 feet for the spacing.

Sometimes the order of the criteria can make a difference in the results. Let's give it a try.

Click in the first column for the Avg/Min Lum Ratio criterion, to give it focus.

Now hold down the Alt key and press the up arrow on your keyboard. This moves it up.

Keep pressing the up arrow until it is at the top of the list.

Now Calculate again.

Success: The Results field shows 198 feet for the spacing and all criteria were achieved. It took 5 iterations this time.

Perhaps, instead of optimizing around our design criteria, we might want to try a specific pole spacing and see how the results turn out.

And how do the Precision Settings affect the outcome?

Let's find out.

Step 5 – A look at Precision Settings

First, let's copy Layout 2 into Layout 3. You can use the Copy command (upper-right corner of dialog), or simply place a dot in the "radio button" for Layout 3.

Next, open the Settings dialog.

Notice that you can change the Number of Decimals. This kind of change can sometimes affect outcome. For example, with Minimum Luminance set to just one decimal place,a calculated minimum of 0.14 would round down to 0.1, but 0.15 would round up to 0.2, making it look like the minimum is twice as high. This in turn would effectively cut the Avg/Min Ratio in half. For this reason, the default number of decimal places in Roadway Optimizer is 2.

Click Cancel; we won't make any changes here.

Next, let's see what would happen if we had pole spacing of 200 feet instead of 198 feet.

Select Calculate Based on Set Spacing.

Next, enter 200 in the Spacing fields for Row 1 and Row 2, just to see how this works.

In this case, Roadway Optimizer won't try to optimize around the design criteria but instead will just calculate the metrics based on this spacing.


After calculating, the results are compared against any criteria with a checkmark and a value entered. Once again, the calculated results will be displayed as red or black, depending on whether the criteria were met. (Even though it wasn't trying to optimize!)

Notice that a 200' spacing did not enable us to achieve all four of our criteria; the Avg/MinLumRatio is displayed in bold red

You may want to keep these settings options in mind as you use Roadway Optimizer in your projects.

Step 6 – Comparison tab: decide which luminaire to use; Export results

The Comparison tab provides a convenient way to compare up to five layouts. Note: In order to compare layouts, the layouts must utilize the same Roadway Standard, have the same number of luminaire rows, and have the same number of lanes.

Click on the Comparison tab. The input parameters and results of the two layouts that we calculated are displayed in tabular format.

Scroll up and down to see all of the input values and calculated results.

Return to the Layout tab.

We can export our results, including grid points and several cycles of our luminaires with the calculated spacing, to AGi32's Model Mode. 

We will use the zlroad2 luminaire from Layout 1. Select Layout 1. 

Be sure that Luminance is displayed. (If necessary, click once on RoadOpt_Lum in the results field.)

Now click the Export button (upper-left corner of Roadway Optimizer dialog).

Roadway Optimizer closes and you are returned to Model Mode. AGi32 is ready to place the luminaires and grid.

Use your mouse wheel to zoom out (roll the wheel back) to give you more working space. 

Click once to place the grid, anchoring its lower-left corner at X,Y coordinates 0,0.

Next, AGi32 is prompting (see the Command Line, lower-left corner of your screen) for the orientation of the grid. An Orient angle of 0 would place the grid in the same position that it had in Roadway Optimizer. An Orient angle of 90 would rotate the grid 90 degrees counter-clockwise. And so on.

Note: You may click your mouse button to indicate the location of the grid's lower-left corner and then the Orient angle, or you may type these values in the field in the lower-right corner of your screen.

For this exercise, enter 45 in the lower-right corner and then hit the Enter key on your keyboard.

AGi32 is ready to place additional grids, if you so desired. However, we will place just this one. Right click to end the command. Click on the Zoom Extents button (Main Toolbar). Your layout should look something like this:

The point-by-point grid has been placed, but we need to calculate it again now that we are in Model Mode. That will be the next step.

Step 7 – Calculate in Model Mode

As we have no objects in this project (aside from the luminaires and poles, let's change the Calculation method to Direct Only. Click on the drop-down arrow next to the Calculate button and select Direct Only Method:

Now click the Calculate button.

The results are displayed in the Statistics field. If it isn't there, click on the Statistics button on the bottom toolbar.

Notice that all of the RP-8-00 metrics are calculated and results shown in the Statistics window: Illuminance, Luminance, Veiling Luminance, and Visibility Level (STV).

Zoom in on the grid. What is displayed here?

Project Manager can help us to answer that question, and to change what is displayed. That is our next step.

Step 8 --Project Manager; change the display.

Click on the Project Manager button (next to the Calculate button).

First, notice all the helpful information in the Hint that opens. Take a look at this information, as it can aid in understanding the Project Manager dialog. Then close the Hint.(If Hints are disabled, enable them from the bottom toolbar button).

Place a checkmark in the Load column for Project_1, if there isn't already one there.

From the Entity Type drop-down menu, select CalcPts.

Notice that there is a checkmark in the Vis column for Luminance (shown here as RoadOpt_Luminance), indicating that it will be visible in Model Mode.

The reason Luminance is visible is because it is the one that was displayed in Roadway Optimizer when we executed the Export command.

The other calculated grids are not checked, and are therefore not visible in Model Mode. However, they have all been calculated and may be displayed without recalculating.

Let's change what's visible. 

Remove the checkmark for Luminance, and place a checkmark in the Vis column for Illuminance (RoadOpt_Illum).

Let's also change the color of the Illuminance grid. 

Click on the down arrow in the Color column for Illuminance. 

Change it to blue.

Click OK.

The point-by-point grid displayed is now blue, showing the Illuminance values:

Tutorial Conclusion

Roadway Optimizer can be a very handy tool in roadway lighting design. It has been greatly expanded beyond its early capabilities, allowing the user to optimize pole spacing for up to four different luminaire types and mounting heights in a layout, and to select from several pavement types (R-Tables) and five different roadway standards. Up to five different layouts may be compared on the Comparison tab.

Calculated results are shown in bold, with achieved design criteria shown in black and unmet criteria shown in red.

What affects the speed of the optimization process?

  • The number of criteria you are trying to meet
  • The number of luminaire types you have in one layout
  • The Maximum Number of Iterations set in the Settings dialog

It is important to remember that many of the settings in the Settings dialog can influence the outcome of the optimization process, as we found in Steps 4 and 5 of this tutorial.

Additional information on Roadway Optimizer can be found by clicking on the Help button while in Roadway Optimizer or one of its secondary dialogs.