Blind Spot Monitoring (BSM) is a driving assistance technology that detects other vehicles in the blind spots behind and to the sides of a vehicle using radar or camera sensors, primarily designed to enhance lane-changing safety. The system activates automatically when the vehicle speed exceeds 10 km/h, monitoring moving vehicles within a range of 3 meters to the sides and 8 meters behind. When a vehicle is detected approaching in the blind spot, it alerts the driver via a warning light on the rearview mirror; if the turn signal is activated at this moment, an audible alarm is triggered. The system employs 24GHz or 77GHz millimeter-wave radar technology, which is less affected by weather and offers higher detection stability compared to ultrasonic and image-based technologies. Some models, such as the 2025 Toyota Corolla, have made it a standard feature, integrating it into the TSS 3.0 intelligent safety system. The system may fail in extreme weather conditions or when sensors are obstructed, so drivers still need to maintain their observation habits. For installation, it typically requires replacing the rearview mirror lens with one equipped with a warning light, enabling non-destructive modification without compromising the original vehicle wiring.
