New high-tech traffic signals being installed on busy 9D could mean fewer traffic headaches for Dutchess County and Orange County drivers. All of this because of new stoplights that will use cameras and computers to detect heavy traffic and keep the lights ahead green so traffic can flow more smoothly.  The traffic improvements also mean work vehicles involved in a billion-dollar water aqueduct project can make quicker trips to construction sites in Wappinger and Newburgh.