1. A vision system for a vehicle, said vision system comprising: an imaging sensor having a forward field of view in a forward direction of travel of a vehicle equipped with said vision system; wherein said imaging sensor comprises a lens and a CMOS imaging array comprising a two-dimensional array of photosensing elements; wherein said two-dimensional array of photosensing elements comprises at least 262,144 photosensing elements arranged in a matrix array of rows and columns; wherein said matrix array comprises at least 512 rows of photosensing elements; wherein said imaging sensor captures frames of image data within said forward field of view of said imaging sensor; wherein said array of photosensing elements comprises groupings of photosensing elements, each grouping having at least three neighboring photosensing elements; wherein at least one photosensing element of each grouping comprises a red light sensitive photosensing element and at least one other photosensing element of each grouping comprises a white light sensitive photosensing element; a control, wherein said control comprises an image processor that processes captured image data to determine a taillight of a leading vehicle present in said forward field of view and traveling ahead of the equipped vehicle in the same direction as that of the equipped vehicle; wherein said control, at least in part responsive to processing by said image processor of captured image data, determines distance between the leading vehicle and the equipped vehicle based, at least in part, on size of the determined taillight in captured frames of image data; wherein said control, at least in part responsive to processing by said image processor of captured image data, determines an angle between the equipped vehicle and the leading vehicle; wherein said control, at least in part responsive to processing by said image processor of captured image data, determines a lateral position of the leading vehicle relative to the equipped vehicle; wherein said control, at least in part responsive to the determined distance to the leading vehicle and the determined angle between the equipped vehicle and the leading vehicle and the determined lateral position of the leading vehicle relative to the equipped vehicle, determines the leading vehicle to be closest to the equipped vehicle as compared to other vehicles present in said forward field of view of said imaging sensor; and wherein said control, at least in part responsive to said determination of the leading vehicle being closest to the equipped vehicle, is operable to at least in part control a braking system of the equipped vehicle.