Two 1975 studies of mass transit systems concluded that subways are much less safe than the streets. Several cities have separate transit police departments to combat this crime wave. Studies have shown that stakeouts by undercover decoys are far more effective than saturation patrols by uniformed officers. Most cities' transit police officials believe that a mix of policing tactics deters crime. Last year, however, New York City responded to public anxieties about crime on subways by putting most undercover officers into uniform. New York's transit system has a high crime rate, a physical layout which makes patrol and surveillance difficult, and an unreliable communications system. Moreover, backup help is usually not available for police officers on late night tours. Although morale is low, New York's transit police chief sees no need for a large undercover force. In contrast, Chicago's mass transit police unit emphasizes the use of decoys. Only the youngest and most physically fit officers are assigned to the transit squad. The Chicago transit system is clean and free of graffiti; smoking is uncommon; and passengers apparently feel relatively safe. Transit squad procedures are informal and morale is high. Washington's Metrorail system has few crime problems. No murders, rapes, or knifings have ever been committed on the system. Designed with security in mind, stations have clear platform spaces, few exits, and no places for criminals to hide. At least eight cameras scan every platform, trains have intercom devices, a uniformed police officer is assigned to almost every train, and undercover officers have recently been added. Photographs are included.