The performance database calculates, by segment, by direction and by year, three hourly performance ratings in each direction for the morning peak period, and three more for the evening period. (For a quick summary of LOS performance ratings, click here.) The Comparative LOS Report allows users to select which highway segments to compare; the software then automatically generates side-by-side LOS tables for comparison.
In these displays, performance ratings are colored to signify mobility: green signifies favorable conditions for drivers (travel at uncongested speeds with plenty of room to maneuver); yellow for heavier traffic conditions; orange for minor congestion at reduced speeds, and red for severe, stop-and-go congestion. The visual impact of a matrix display that is mostly green contrasts sharply with a display that is mostly orange or red. At a glance it is easy to see where, when and in what direction mobility is most seriously impeded. Since surveys are repeated every few years, matrix displays from different years are placed side-by-side to reveal the presence or absence of trends.
Important note: When viewing these tables, it must be understood that traffic flows are variable (most individual ratings are based on four observations across four different days, minus the effects of confirmed or suspected incidents). Accordingly, individual ratings can vary from one hour to the next or one year to the next even though significant change has not actually occurred. It is therefore necessary to take a general view of each table, filter out the 'noise' of ordinary variations, and focus on the larger changes characterized by significantly changed color displays.
A detailed description about Performance Measures and what the various colors and letters in this report mean is available in the Survey Information section of the website, or by clicking HERE.
These report graphics may be printed or saved to an html format directly from the browser, for later viewing with your browser. There are also two options for exporting. The first option is to capture your screen display directly using the 'Print Screen' key on your keyboard; then use the 'paste' command (control-V) to insert the screen display into documents created by other application programs (such as Microsoft Powerpoint or Adobe Photoshop). Second, if your computer is equipped with Adobe Acrobat (full program, not just the Reader), you can use the 'Print' command to export to a digital PDF file (select 'Adobe PDF' as your printer). Once the file has been exported to PDF, you can open, print, edit or copy/paste as you would any PDF file.