NCJ Number
173008
Journal
FBI Law Enforcement Bulletin Volume: 67 Issue: 5 Dated: May 1998 Pages: 6-9
Date Published
1996
Length
4 pages
Annotation
This article presents the methodology and findings of a study that examined police officers' ability to distinguish between lethal and nonlethal objects under low-lighting levels.
Abstract
The experiment used 12 police cadets as subjects. All subjects had corrected 20/20 vision, and none had eye disease. Each cadet was shown three nonlethal objects and a large-frame handgun under each of four incrementally increasing levels of low light. A black jacket served as a background for the object, and an assistant stood behind an opaque partition that was quickly lowered for 1 second for observation by the subjects. The assistant did not point the object in the direction of the cadet, but held each object in a clenched fist close to his body, similar to the physical circumstance of many shooting incidents. The nonlethal objects consisted of a 6-inch piece of green garden hose, an 8-inch piece of black pipe, and a 6-inch chrome-plated screw driver. According to police documents, officers had misidentified similar objects as lethal during the past 10 years. The experiment used several lighting levels. These levels ranged from .04 foot-candles to .45 foot-candles. For comparison, a bright, full moon on a clear night exhibits illumination comparable to a .01 foot-candle lighting level. A person standing 30-40 feet from the direct beam of a vehicle's headlights at night compares to a .45 foot-candle lighting level. The study showed that police officers have difficulty differentiating between lethal and nonlethal objects illuminated by less than .50 foot-candles of light, the level often encountered during routine police working conditions at night. Officers should increase lighting levels by using their car's headlights and flashlights with halogen bulbs. A weapon-mounted lighting device, attached to the muzzle of an officer's weapon can increase visual ability in low-level lighting conditions. In addition, officers should train in low-level lighting conditions. During the investigation of an officer-involved shooting, police administrators should document the lighting level at the time of the incident with an illuminometer and consult a vision expert with experience in this area. 1 table