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Law Enforcement Vehicle Lighting and Reflectivity Studies: An Overview 

NCJ Number
Date Published
14 pages
This study examines the history of lighting and reflectivity for emergency vehicles, going back to the early 1980s, with a focus on law enforcement vehicles.
Emergency lighting has two purposes: 1) to alert motorists to the approach of an oncoming emergency vehicle; and 2) to alert motorists to an emergency vehicle stopped in the roadway. In the United States, agencies use five main colors of emergency vehicle lighting: red, amber, white, green, and blue. Emergency vehicles use four main types of lighting: rotating lights, fixed flashers, strobe lights, and light-emitting diode (LED) lights. The advent of LED lighting has made emergency lighting more visible and brighter. It is also preferred for emergency vehicles due to its compact size, greater efficiency, and more intense colors. For reflectivity, the study concludes that contrasting chevrons warn approaching drivers of a stopped emergency vehicle. Reflective striping that outlines the emergency vehicle gives drivers a better sense of an emergency vehicle's size and shape. Retroreflective badges or agency seals improve visibility and recognition; and retroreflective material concentrations low on emergency vehicles optimize oncoming vehicles' headlights. Regarding emergency lighting, red lights are more visible in the daytime, and blue lights are more visible at night; color combinations are best. Flash rates for emergency vehicles should be faster for approaching vehicles and slower for vehicles stopped in the roadway. Drivers should not be drawn to an emergency vehicle's flashing lights. Scientific studies indicate that there is no proof that strobe lights on emergency vehicles cause seizures in epileptics. Comments are also offered on reflective vests. 25 notes

Date Published: January 1, 2019