There are four types of traffic sites on the AL Traffic Data Manager (TDM) application: Permanent, Portable, Control, and Virtual.

Site Definitions

Permanent counter sites are the Continuous Count Stations (CCS) located around the state. These sites monitor traffic all year round by utilizing a variety of different sensors (i.e. inductive loops, radar, infrared detection, etc.).

Portable counter sites collect short duration vehicle classification and/or volume counts. The count duration is typically either 48 continuous hours that will incorporate 2 or 3 days depending on when placed or 168 continuous hours that will incorporate 7-8 days depending on when placed. Every attempt is made to collect traffic data at these locations on a minimum three-year cycle.

Control counter sites are no longer used since 2018.

Virtual counter sites are similar to portable counter sites but get their AADT from another site.

Traffic Site Colors

Traffic sites can be displayed on the map as points. Each type of site will be displayed in a different color. The following colors will be used by default:

• A Red dot () will indicate a Permanent Site.
• A Green dot () will indicate a Portable Site.
• An Orange dot () will indicate a Control Site.
• A Purple dot () will indicate a Virtual Site.

Legend

If the plus sign () is selected for the first two legend entries, the user will be able to view the four traffic types and their associated colors, as described above. The permanent and portable traffic sites will automatically be checked on the Legend and therefore displayed on the map. As the user zooms in, these sites will be visible on the Map Frame. The image below shows an example of the permanent and portable traffic sites on the map.

Find Traffic Sites

The user can also search for certain traffic sites using the icons and fields in the "Find Traffic Sites" section of the Map Tab. To learn more about that process, click here.