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Emergency Lights for Slicktop Vehicles

Written by PFM Staff

Many patrol officers, detectives and police administrators using slicktop or semi-marked sedans drive the vehicle as if the motorists around them can actually see their tiny emergency signal. These officers drive like they did with their fully marked sedan, the one with a roof-mounted lightbar that gave a full 360 degrees of coverage.

That little dash rotator doesn’t cut it any more. No one sees the lights hidden behind the finned intakes of the grille. These small emergency signals are barely effective directly in front of the vehicle, are truly worthless from an angle, and are absolutely invisible from the side. The lack of a 360 degree warning signal is a clear liability. Remember, we don’t “have” the right-of-way. We only “request” it.

If you don’t think your police vehicle, one that moves in violation of traffic laws, needs 360-degree coverage, brush up on California v. Hudson, a 2006 California Supreme Court case. So, what emergency lights really are required for a slicktop police sedan? How can we get a real 360 degrees of coverage emergency light coverage, at the lowest cost, the lowest amp draw, and the highest service life?

No Gaps and Not Too Much

The assumptions are two-fold, 1) absolutely no gaps whatsoever in the 360 degrees of coverage around the police car and, 2) no overkill with light output in any one direction. Any vehicle traveling under the color of law should signal that intention in all directions. You pick a direction that it is OK for a police vehicle not to visually signal a warning, and some lawyer will prove a lack of signal from that direction caused the injury to his client.

In fact, an argument can be made that a signal angled to the front and a signal directly out the side is more important than a signal straight forward and straight backward.

The other extreme is too much light. We need enough light to signal the motorist, period. More light than that confuses the motorist, attracts the motorist or blinds the motorist. More light than that fills the windshield or rear window with clutter and obscures our vision. More light that that drives up the cost of the upfit unreasonably. More light than that pulls more amps than necessary.

Based on recent Florida Highway Patrol tests, more light than that blends the colors of light together, and the unique message sent by different colors of light is lost.

Best Forward Signal

It starts at the front with wig-wag headlights. Wig-wags give a clearer, stronger, more unique signal than anything else we do to an emergency vehicle. Motorists may not know if it is a police, fire or EMS vehicle, but they know instantly it is some kind of “emergency” or “public” vehicle, so our most important message has been successfully received. Flash the rear taillights when you flash the headlights.

Next, the main forward emergency signal. This can be any of dozens of dash, rear-view mirror, headliner or sun visor-mounted emergency lights. A headliner-mounted interior bar gets the emergency lights high, i.e., close to the height of a lightbar. It is out of the airbag deployment zone and keeps the dash uncluttered for pedestrian and other vehicle visibility.

Angled, Intersection Signal

Next, move to the front quarter of the vehicle for that critically important intersection warning. Yes, the Fresnel pattern on many LED lamp modules spreads the light signal to the side…a little. Nothing, however, achieves the angled intersection warning signal like LEDs mounted on the outside rear-view mirrors. LED outside mirror lights should be on every emergency vehicle that doesn’t have a lightbar.

Some outside mirror lights are custom molded for the mirror housings of the Charger, Ford CVPI and Impala. Some are bolt-on modules added to the outside of the existing factory housing. In any event, getting the wiring routed through the inner door, and under the outside mirrors is a bit of a project.

Broadside Warning

The single most overlooked lighting aspect on a slicktop emergency vehicle is the side warning. Looking at the side of a slicktop car, it is virtually impossible to see any warning light at all. Yet, slicktop cars park sideways and at odd angles to incidents and traffic flows all the time. When this happens, all the light goes out the front and the back, where it is of little use, and no light goes out the side…not headlights….not factory flashers. You end up with an unlit car, sideways on the road, at night.

B-pillar lights should be on every emergency vehicle that doesn’t have a lightbar…even if it has angled mirror lights. B-pillar lights can be mounted to the prisoner partition, to the B-pillar or to the side door trim panel. Most lie flat enough that it fits under rear window protection bars.

The Rear Lights

Like the dash (front) lights, a huge variety of deck (rear) lights exist. Some are mounted low on the package tray, while some are mounted to the headliner. Of course, some are also positioned right in the middle of the back glass, which totally obscures the driver’s rear view.

The deck-mounted interior lights avoid most application problems. It is very easy to bolt directly (and firmly) to the steel skeleton under the package tray. This is a low-profile location and allows the maximum visibility out the rear window. On the Ford CVPI, with the deck-mounted third brake light, most of these full-width lightbars are mounted on either side of the brake light housing. Again, a number of internal lightbars designed for the rear deck exist from virtually all emergency light makers.

360 Degrees of Light

You are done. You have 360 degrees of coverage without any more expense or amp draw than absolutely necessary. Walk around the car to see…wig-wags, front headliner, outside mirrors, B-pillars, rear deck. This setup meets our goal of complete coverage with the minimum lights, minimum expense and minimum amp draw.

The strongest signal is forward, which makes sense. You have wig-wags and headliner. The intersection gets split coverage, off-axis lights from the front headliner lights and direct lights from the mirrors. Side coverage is off-axis lighting from the mirrors and direct coverage from the B-pillars.

The weakest coverage is output to the angled rear, which is the least critical. But you still have off-axis coverage from the B-pillar and off-axis coverage from the rear deck. Finally, the second strongest signal is out the back with multiple combinations of color and flashed taillights.

Grille and Corner Lights?

For most upfits, grille lights are simply not needed. The slicktop vehicle is unlikely to have a push bumper to mount the LED modules. Hidden behind the grille, the lights are visible only from the front through the tiny air intake slots. Mounted behind the grille, they have zero off-axis coverage. Grille lights are also well below the motorists line of sight, thus invisible in heavy traffic. Grille lights should not be necessary with a full-width headliner bar.

It seems that a police car is not a police car unless it has corner lights. These are simply not necessary to give the full coverage. If these lights are simply wanted, rather than needed. They can be mounted in the headlight bezels and backup light housings. But these are not substitutes for the other lights we have already discussed. Use them only in addition to the outside mirror and B-pillar lights, not in place of them.

Published in Law and Order, Apr 2009

Rating : 6.3


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