A vehicular driving assist system includes a sensor disposed at a vehicle and operable to capture sensor data. An electronic control unit (ECU) includes electronic circuitry and associated software, and the electronic circuitry includes a data processor for processing sensor data captured by the sensor. The vehicular driving assist system, via processing at the data processor of sensor data captured by the sensor, detects a tread of a tire of the vehicle. The vehicular driving assist system determines a tread depth of the tread of the tire. The vehicular driving assist system, responsive to the determined tread depth being below a threshold tread depth, generates a worn tire signal to alert a driver of the vehicle that that the determined tread depth is below the threshold tread depth.