PC-LOS

PC-LOS is the software you use to process the data you collect in the field to find the Level Of Service at signalized intersections. Typically you run this software in your office on a desktop computer. Here are a few of the basic screens from the software. The screens show the typical sequence you would follow to process GPS data collected in the field, edit the runs, create a study, and print a report.

Startup Options
This is the screen you see when you first run the program. It is the starting point for each session. Each large green square is a button; you just click on the button you want to execute the command.

A typical study would use data collected with the GPS2LT software, so we would click on that button.

The data collection is a little different for PC-LOS since you are only interested in one intersection at a time. In the field you drive through the intersection as many times as possible during the peak traffic times, choosing the approaches that likely have the most delay (you usually know this in advance). Each pass through the intersection is one run.

Data Plot
This screen is where you set the start and end of the control delay for each run, which is the current basis for Level of Service. This is tricky to do automatically but easy to do visually. You move the left vertical line to the point where the car first started to feel the congestion and set the right vertical line to the point where the car was back up to a free flow speed. You also can set the ideal speed for that run (the speed the car would drive without any congestion). The software calculates the delay and shows it in the text box on the side of the screen. You do this for each run in the study, which only takes a few seconds each.

Study Summary
This is the main screen of the software. It shows the runs you have selected for this study. Runs that have had the control delay points set are shown in green. Once all of the runs in the study are set the software shows the results of the LOS analysis on those runs (at the bottom of the screen). The software calculates the Average Control Delay which is simply the average of the control delays found in the runs. This is converted into an LOS Grade for the study. You also can enter some study parameters that are saved with each study and printed on the report.


	LOS Summary Report The software has a simple report that shows the information from the Study Summary screen. There isn’t much to report when the answer is a letter from A to Z.

These four screens just give you a brief introduction to the PC-LOS software. To learn more about the software you can download the program and try it out. It will install in a Demo mode, which is the full program but slightly crippled so it can’t be used for real studies. You can also download the PC-LOS Manual which has a complete description of the program and how to use it. There also is a paper called “How To Measure LOS in the Field” which discusses why PC-LOS was developed and how you can use it in your work. You also can view the tutorials on the Tutorials page which provide more information about different aspects of the software.