When the Town of Babylon installed global positioning system technology in most of its fleet of 250 vehicles in January, officials touted it as a way to improve efficiency, particularly during emergencies such as snowstorms. However, the system also is being used to monitor worker behavior -- a realization that has left town .employees increasingly nervous. One of a growing number of municipalities and corporations around the country using GPS to track workers, Babylon has become the local flash point in the debate over how to balance the desire to improve efficiency with the need to protect worker privacy. Already,...