Photo Dale Stockton
LEDs project most light forward. Photo JP Molnar
FEATURED IN TECHNOLOGY AND COMMUNICATIONS
As cops, we like bright lights that tell people to get out of our way. We don t like getting hit by a car when we re on a traffic stop or at a crash scene. At the very least, it destroys our office; at the most, it kills us or someone else.
The latter has caused a lot of debate about what constitutes the best emergency warning system. Remember the great television show Emergency! ? The show, which debuted in 1972, showcased the latest lightbar technology, the now legendary Federal Twinsonic Lightbar, on Squad 51. That lightbar changed the idea of overhead lighting on emergency vehicles. Since then, the solid lightbar concept has remained relatively the same, with the exception of advancements to the light sources, such as strobes and LEDs.
Several years ago, one of my squadmates got a new Ford Crown Vic for patrol that formerly functioned as a tradeshow vehicle for an emergency lighting manufacturer. We were working graveyard, and I remember the first time he showed up to a cover call with a multitude of LED lights blazing in every direction. The car could be seen from space, but was it really safer?
To find out, I researched some of the leading studies conducted on the effectiveness of emergency lighting. Although numerous studies have been conducted on the perception of light by motorists, one landmark study specifically addresses two routine problems in law enforcement: police vehicles and officers being struck on traffic stops and crash scenes, especially
at night. The study, released by Lieutenant James D. Wells Jr. in 2004 on behalf of the Florida Highway Patrol (FHP), concentrated on emergency lighting configurations.
The study covers much more than I can address here, but I m including a synopsis of what should be a mandatory read for anyone charged with buying their agency s emergency lighting. Doing so could save money, aggravation and, more importantly, an officer standing on the side of the road.
Wells FHP Emergency Lighting Study
According to FHP statistics, from 1996 2000 there were 1,793 incidents in which Florida motorists crashed into emergency vehicles. As a response, the FHP and Wells began a comprehensive study designed to reduce that number. The study was all encompassing, but I ll focus on Wells evaluation of three different then-prototype lighting systems from Code 3, Federal Signal Corporation and Whelen Engineering. The study s emphasis was placed on human reaction to various lighting configurations relative to perception and action behaviors.
As far back as the ancient times, man used light in the form of fire to guide travelers or to warn them of impending risk. A few thousand years later, we re still at it, bolting red and blue lights to the roof of our patrol vehicles to both identify and warn motorists of law enforcement s presence. As motor vehicles have become faster and emergency lighting sources brighter, the general trend has been to put the most and brightest amount of lighting on a patrol car to provide the earliest warning times.
What s missing is the critical component of lighting s goal. As Well s study points out, the most important purpose of emergency lighting is to deliver a specific message to drivers. But what message? Are you simply trying to announce your presence, tell them to get out of the way, warn them of an upcoming hazard or use lighting to create a traffic pattern?
Activating bright lights without considering your reasons may do more harm than good. For instance, those lights might actually decrease the driver s ability to see emergency responders who are on foot working a traffic accident or debris that is in the roadway.
A second consideration: Proper lighting can communicate the position and current action of your vehicle. Motorists perception of distance and motion can prove problematic. Simply put, it s hard for people to tell if your car is moving or stopped when they approach you.
Wells points out numerous guides that motorists use to gauge distance from and reactions to other vehicles, including familiarity with the road and other objects, visual angle, the relative size of one object vs. another, elevation changes, clarity and perceived closing speed. Despite having excellent visibility and no physiological issues, drivers routinely crash into stopped or slow-moving vehicles because of difficulty judging closing speed, especially at night. That s why officers with all of their rear lights activated on the side of an arrow-straight road with no obstructions still get rear-ended.
Given a similar situation, it may make more sense to use emergency lighting to direct or condition motorists to use proper avoidance behavior, rather than just alert them of your presence.
The Moth Effect
Should you leave your emergency lights on during a traffic stop? Proponents claim the emergency lighting attracts attention and warns motorists of your presence and any possible hazards. Detractors claim that because people naturally drive where they look, the lights will actually attract them, especially impaired drivers, like a moth to a light bulb. As a result, some agencies require officers to extinguish all rear-warning lights on a freeway traffic stop, while other agencies leave it to officer discretion.
According to Wells, no known studies substantiate the notion that activated emergency lights cause drivers to crash into stopped police cars. He points out, and I agree, that there are numerous things drivers look at while on the road, including road signs, billboards, store fronts, etc., and no one seems to regularly drive into those items. In fact, an analysis of rear-end collisions by the FHP and the Illinois State Police determined no evidence supports the moth effect.