The invention provides a retractable cover apparatus, which when extended to cover the wheel or track area of a variety of vehicles minimizes the amount of spray and debris flying from the tires or tracks of the vehicle. The cover system is mounted to the frame of a vehicle without requiring extensive modifications to the frame, and includes, for each side of the vehicle, an elongated flexible cover having first and second ends and a width sufficient to extend laterally outwardly beyond an outer extent of the wheels or tracks of the vehicle. The cover system also include at least first and second cover housings, one of the housings adapted to contain the cover in a rolled retracted condition and the other housing being adapted to anchor a free end of the cover in an extended condition thereof. At least one support bar is removably mounted to the frame of the vehicle over which the cover is supported. When the cover is required, it is pulled from the one cover housing, over the support bars and is anchored in place at the other cover housing.