- Green – Friendly dog, likely to be open to interaction
- Yellow – Caution: The dog is nervous, in training, or unsure of strangers
- Red – Stop and give space: The dog may be reactive, anxious, or doesn’t like being approached
- Blue – Often worn by service dogs or dogs in active training
While not every dog owner uses this system, more and more people are adopting it — especially in dog parks, walking trails, or neighborhoods with lots of pets.
Why Red? The Psychology Behind the Warning
Red has long been associated with “stop,” “caution,” or “danger” in human settings — from stop signs to warning labels. It draws the eye. It alerts the brain. And for dogs who need extra space or boundaries, a red collar acts as a polite way to say, “Please give me room.”
