Configuring IntelliSight Devices: Zones Explorer

Assigning a Speed Condition

The speed conditions is used to trigger an output, based on the average vehicle speed for the specified sample count. A zone with this type of condition would normally be set upstream from an intersection. The output could be set to activate a sign or hold a phase at an intersection. Example 1: Sign Activation Set the condition so that if the detected traffic speed is less than the defined threshold speed, a sign placed upstream from the zone could be activated to indicate a slow traffic condition ahead. Or, if the detected speed is greater than the threshold speed, a sign could be activated to instruct the driver to slow down. Example 2: Hold Phase at Intersection If traffic travels at a speed that might make it impossible to stop in time for the phase change, an output could be sent to signal the controller to hold the phase to allow time for the vehicle to get through the zone safely. When setting up the Speed condition, the sample count and dwell time determine when the condition is activated (ON) and deactivated (OFF). The following shows the ON/OFF sequence when: Threshold = Greater than; Speed = 20; Dwell = 5 seconds; Sample count = 3

In the graphic above, Count Group 1 is created after the first three vehicles are detected (Count=). The average speed of the group is greater than 30 (Speed=) causing the condition to activate (turn ON) and remain active for a period of five seconds (Dwell=)before turning OFF. Count Group 2 is created when vehicle V4 is detected after the dwell time expired. The speed of vehicle V1 (32) from Group 1 is dropped and the speed of vehicle V4 (27) is added, creating an average that is not greater then the set limit, so the condition remains inactive (stays OFF). Count Group 3 is created when vehicle V5 is detected. The speed of the first vehicle from Group 2 (31) is dropped and the speed of vehicle V5 (35) is added, making the average above 30 and causing the condition to activate again. However, before the set dwell time expires, vehicle V6 is detected, creating Count Group 4, whose average is still above 30 causing the condition to remain ON and a new dwell period to begin. To set up a Speed condition, do the following.

• In the Zone Explorer section, click the plus sign (+) to the right of the zone description and select Speed.

2. Click the drop-down indicator to the left of Vehicle Speed.

3. Use the drop-down menu to select the Threshold.

• Greater Than: The condition is met when the detected speed is greater than the value for Speed.
• Less Than: The condition is met when the detected speed is less than the value for Speed.
• Between: The condition is met when the detected speed is between the values for Lower and Upper.
• Outside: The condition is met when the detected speed is less than the value for Lower or more than the value for Upper.

4. For Speed, select or enter the speed when the threshold is Greater Than or Less Than. 5. For Lower, select or enter the lowest speed to be used when the Threshold is Between or Outside. 6. For Upper, select or enter the fastest speed to be used when the Threshold is Between or Outside. 7. For Dwell, select or enter the maximum number of seconds the condition is held active (ON) without a new vehicle being detected. At the end of the specified time, the condition will go inactive (OFF). If another vehicle is detected before the dwell time expires, a new count average is calculated. If the new average drops below the set speed, the dwell period continues to its expiration. If however, the new average keeps the condition active, the old period ceases and a new dwell period begins. Example: Speed = 30, Dwell = 1- If the condition is active and a new vehicle is detected that brings the average below 30, the dwell period continues to the end of the 10 seconds. If the new vehicle is detected 3 seconds into the 10-second dwell time and it keeps the average above 30, the current dwell time stops and a new 10-second dwell time begins. 8. For Sample Count, select or enter the number of vehicles to be used in sampling for an average speed. NOTE: A sample count of one (1) does not use averaging. 9. Use the drop-down menu to select an output to be sent to the controller when the Speed condition is met.
To change the initial state of the output or to set the output options, use the Action Explorer.
10. When all conditions and actions have been defined, click APPLY CHANGES.

Version 4.5.0 - Copyright © 2025, Image Sensing Systems, Inc. All rights reserved.