A road condition is classified based on spray water occurring at a wheel of the vehicle. To this end, the space around a wheel of the vehicle is imaged by a camera and the image captured by the camera is analyzed to detect spray water therein. A distinction can be made between a dry road, a wet road or a road having a risk of aquaplaning on the basis of the detected spray water, e.g. based on the angle, direction or projection range of the spray water.