Smart Ambulance Traffic Signal Preemption System Using Transponder Radio Transmission

Traffic congestion at signalized intersections is one of the major causes of delay for ambulances during emergency response. Even a short waiting period at a traffic signal can affect the ability of an ambulance to reach a hospital or emergency location quickly. This paper presents a prototype smart traffic control system designed to provide priority passage to ambulances at road intersections. The proposed system uses a dedicated control panel operated by a traffic police officer or control room operator. When an ambulance approaches a traffic signal, the operator presses a direction-specific push button on the transmitter unit. The transmitter sends a 433 MHz radio frequency signal to the receiver unit connected to the traffic signal controller. After receiving the command, the receiver activates the signal path for the ambulance and blocks traffic movement from the remaining three directions. The prototype uses Arduino Uno boards on both transmitter and receiver sides, push buttons, a 433 MHz RF transmitter and receiver pair, traffic signal LEDs, a NeoPixel LED, buzzer, Bluetooth module, and a basic application interface for ambulance movement and manual control demonstration. The system was evaluated through prototype-level testing rather than full-scale field deployment. The observed demonstration shows that the proposed design can represent emergency signal priority logic in a simple, low-cost, and understandable manner. The paper discusses the system architecture, working principle, hardware implementation, software demonstration, advantages, limitations, and future development scope.