CitRad: A Low-Cost Open-Source Citizen Science Radar System to Democratize Urban Traffic Monitoring

Urban traffic monitoring is critical for addressing congestion, speeding, and safety concerns in rapidly urbanizing areas. This paper presents CitRad, a low-cost, open-source Doppler radar system designed for citizen science applications, enabling communities to collect and analyze traffic data independently. The system employs commercially available components, such as a 24 GHz Doppler radar module and the Teensy 4.0 microprocessor, ensuring affordability and ease of assembly. Key features include a dynamic noise floor adaptation for robust target detection. Initial measurement campaigns demonstrated the system’s ability to accurately monitor traffic speeds, vehicle lengths, and passing distances, as well as detect specific patterns such as pedestrian and cyclist movements.