Bright green lights on a car aren’t just decorative—they signal an emergency medical service vehicle, like volunteer EMTs or non-emergency ambulances, transporting patients to treatments or appointments. These lights ensure smoother passage through traffic for critical healthcare needs. Strict regulations limit their use to registered medical services, and unauthorized use is illegal, risking confusion and delays. When you see green lights, yield the way—they carry quiet urgency, helping patients reach care on time. Your small act of pulling over can save crucial moments for someone in need.