1. A driver assistance system for a vehicle, said driver assistance system comprising: a camera disposed at a vehicle equipped with said driver assistance system, wherein said camera views forward of the equipped vehicle and wherein said camera is operable to capture image data; a control device comprising an image processor; wherein said image processor is operable to process image data captured by said camera; wherein, responsive to processing of captured image data by said image processor, said driver assistance system is operable to adjust a light beam emitted by a headlamp of the equipped vehicle; wherein said control device, responsive at least in part to image data processing by said image processor, is operable to determine when the equipped vehicle is at least one of (i) approaching a construction zone, (ii) entering a construction zone and (iii) driving along a construction zone; wherein image data processing by said image processor comprises at least one of (a) traffic sign recognition, (b) character recognition, (c) object detection, (d) object recognition, (e) spectral discrimination, (f) spatial recognition and (g) lane marker detection; wherein determination that the equipped vehicle is at least one of (i) approaching a construction zone, (ii) entering a construction zone and (iii) driving along a construction zone comprises spectral recognition of an orange construction sign; wherein, responsive to determination that the equipped vehicle is at least one of (i) approaching a construction zone, (ii) entering a construction zone and (iii) driving along a construction zone, said control device enters an enhanced mode that enhances image processing of captured image data by said image processor to discriminate orange construction zone signs from taillights of leading vehicles so as to adjust the light beam emitted by the headlamp of the equipped vehicle to a higher beam state when no taillights of leading vehicles are present; and wherein, responsive to determination of the equipped vehicle exiting the construction zone, said control device returns to a normal mode to adjust the light beam emitted by the headlamp of the equipped vehicle responsive to determination of headlamps of approaching vehicles and taillights of leading vehicles.