1. A vision system for a vehicle, said vision system comprising: at least one imaging sensor having a forward field of view with respect to a forward direction of travel of a vehicle equipped with said vision system, wherein said at least one imaging sensor comprises a lens and a CMOS imaging array comprising a two-dimensional array of photosensing elements, and wherein said at least one imaging sensor captures image data representative of objects present in said forward field of view; at least one register operable to access photosensing elements of said array of photosensing elements; wherein said array of photosensing elements comprises a plurality of sub-arrays, said sub-arrays each having at least three neighboring photosensing elements; wherein at least one photosensing element of each sub-array comprises a red light sensitive photosensing element and at least one other photosensing element of each sub-array comprises a white light sensitive photosensing element; a control responsive to said at least one imaging sensor; wherein said control processes image data captured by said at least one imaging sensor to determine an object present in said forward field of view; wherein said control processes image data captured by said at least one imaging sensor to determine a distance between the equipped vehicle and the object determined present in said forward field of view; and wherein said control discerns if the determined object is an oncoming vehicle or a leading vehicle at least in part in response to rate of approach of the determined object to the equipped vehicle.