Ever seen a car with bright green lights and wondered what it was about? At first glance, it might seem like a festive touch or an early celebration. But these lights aren’t just for show—they serve a real and important purpose. Green lights on vehicles are a sign that the car is part of an emergency medical service. When you spot one, it’s a signal to yield the right of way—because someone inside could be heading to receive critical medical attention.

You’ll typically see green lights on volunteer EMTs, private medical transport services, or non-emergency ambulances. While these vehicles aren’t rushing to life-threatening situations like traditional ambulances, they’re still on important missions, transporting patients to necessary treatments, dialysis, or healthcare appointments. The green light ensures they can move through traffic more efficiently and avoid delays that could impact a patient’s health or well-being.

It’s important to note that not just anyone can slap green lights on their car. In most places, strict regulations govern their use. Drivers must be registered with local or state authorities and prove they’re affiliated with a legitimate medical service. Unauthorized use of green lights is not only illegal but could lead to confusion on the road and cause critical delays for actual medical vehicles. If you suspect misuse, it’s essential to report it to the authorities.