1. A vision system for a vehicle, said vision system comprising: a forward facing camera configured to be disposed at a windshield of a vehicle equipped with said vision system, wherein, when disposed at the windshield of the equipped vehicle, said forward facing camera has a forward field of view through the windshield of the equipped vehicle; said forward facing camera comprising an imaging array sensor and a lens; wherein said forward facing camera is operable to capture image data for an adaptive speed control system of the equipped vehicle; an image processor operable to process captured image data; wherein, responsive at least in part to processing by said image processor of captured image data, lane markers of the road along which the equipped vehicle is traveling are detected; wherein, responsive at least in part to processing by said image processor of captured image data, other vehicles exterior the equipped vehicle are detected; wherein, responsive at least in part to processing by said image processor of captured image data, road curvature of the road along which the equipped vehicle is traveling is determined; wherein, responsive at least in part to processing by said image processor of captured image data, entering of the equipped vehicle into a road construction zone is determined; and wherein, responsive to the determination that the equipped vehicle is entering into the road construction zone, speed of the equipped vehicle is automatically reduced.