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; 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 determines the distance between the equipped vehicle and the determined object at least in part in response to at least one of (i) size of the determined object, (ii) position of the determined object, (iii) light intensity of the determined object, and (iv) rate of approach of the determined object,