How Vehicle Loops Work

How do loops work? While many think loops work off magnetism, they work off inductance. Any material that is a good conductor of electricity (like metal) can be detected by inductance loops. Loop detectors require a percentage of change to trigger a detection, which means that enough metal needs to enter the detection field to trigger a detection. Depending on how sensitive the system is, an object as small as a metal trash can lid can trigger a detection.

How many loops does my system need?

If you have a slide gate, cantilever gate, vertical lift gate, or vertical pivot gate, you need two loops. If space permits, you may want to install an additional exit loop further down the driveway so the gate will be open by the time the vehicle reaches the gate.

(1) Inside Reverse or Exit Loop
(1) Outside Reverse Loop
(1 Optional) Extra Exit Loop

If you have a swing gate, you need three loops. If you have enough space, you may want to install an additional exit loop further down the driveway so the gate will be open by the time the vehicle reaches the gate.

(1) Inside Reverse or Exit Loop
(1) Shadow Loop underneath the gate swing path
(1) Outside Reverse Loop
(1 Optional) Extra Exit Loop

What's the difference between a reverse and exit loop?

Exit loops automatically open the gate when a vehicle drives over them. They also will hold a gate open and reverse a closing gate, which means they can be used in place of an inside reverse loop. Reverse loops will reverse a closing gate if a vehicle is detected. A reverse loop will also hold a gate open if a vehicle stops over the loop. If a gate is fully closed and a vehicle drives over a reverse loop, nothing will happen; the gate will not open.

For More Information On Loop Sizes, See Our Loop Size Chart For Reference.
About Direct Burial Loops About Saw-Cut Loops