A detailed study of warning signs with flashers in school zones was conducted by the Kentucky Department of Transportation to determine the signs' effectiveness in reducing the speeds of vehicles during times of pedestrian activity. Field investigations were conducted at all of the 120 flasher locations in Kentucky Highway Districts 6, 7, and 9. About 14 percent of the flashers were inoperative, and such problems as nonuniform signing, hidden flashers, deteriorating signs and pavement markings, and poor sight distances were also found. Speed studies were conducted at 48 locations. Average speed reductions were found to be only 3.6 mph during flashing periods. Signs and flashers at high-speed (55 mph) locations increased the potential for intervehicle accidents due to decreased speed uniformity. Crossing guards caused reductions in vehicle speeds to within the 25 mph limit. Speed enforcement, minimal periods of flashing, good sight distance, and proper maintenance of signs and flashers were shown to improve their effectiveness in reducing speeds. (Author/JG)