A video-based vehicle headlight state monitoring method and system. A vehicle image can be captured by an image-capturing unit and converted to a grayscale image. The grayscale image can be processed to locate a front license plate and identify a position of a headlight region in front of the vehicle utilizing an algorithm. An average digital count with respect to brightness of the headlight region can be compared with average digital count with respect to brightness of several parts of the vehicle and a background region to determine the vehicle headlights ON/OFF status. The headlights can be considered ON if the digital count level of the headlight region is higher than the digital count of the several parts of the vehicle and the background region. A warning signal can be initiated to turn the headlights on during a special situation utilizing a signal generator.