Smart Traffic Signal Preemption System for Ambulance Clearance Using IOT

This system addresses life-threatening delays caused by traditional, inflexible traffic management at urban intersections. The architecture utilizes an IoT-based framework where sound sensors distinguish ambulance sirens from ambient noise to dynamically activate a green corridor. Specifically, a sound sensor placed 120 meters from an intersection identifies the approaching vehicle's sound level, while a second sensor near the traffic pole confirms clearance, allowing the system to revert to normal operation. To ensure reliable long-range communication, the system integrates LoRa (Long Range) technology for signal transmission and reception between the ESP32 controlled components. Experimental results indicate this automated approach is significantly more efficient than GPS or image processing, reducing 50km transit times to approximately 20 minutes. By combining LoRa connectivity with acoustic sensing, the system provides a cost-effective solution to prioritize emergency vehicles and save human lives. Keywords — sound sensors, IoT (Internet of Things), Arduino UNO, traffic light, Ambulance, LoRa (Long Range), traffic signal preemption, siren detection, green corridor, emergency vehicle clearance.