An Emergency Vehicle Preemption (EVP) system, often called an Opticom, helps emergency vehicles move safely through intersections by turning traffic signals green in their direction. A white light near the traffic signal shows when the system is active. A flashing white light means an emergency vehicle is coming from another direction. A steady white light means an emergency vehicle is approaching from behind you in your lane.

When you see the white light, slow down, stay alert, and be ready to yield. If you are already in the intersection, continue through it, and then pull over when it’s safe so the emergency vehicle can pass.