The use of strobes in tactical flashlights*

Koen van der Linden has been on the Dutch police force since 1972, in eight different units and special arrest squads, and has more than a decade of experience as a training officer in hand-to-hand combat and firearms training for regular and special force officers in Holland.

The situation in Europe, he says, is very different to the USA – law enforcement officers do not “go from door to door, armed with rifles to take out hostage takers or town guerrillas.” In 2012 in Amsterdam, for example, there were 19 incidents in which police fired handguns, and 15 of those were warning shots. “99.9% of all incidents are non-weapon-related – drunk people that won't leave a bar, women molesting their husbands, thieves resisting arrest…”

While shooting incidents in Holland are rare, incidents in which firearms and flashlights are used together are even more unusual: “I know of every shooting incident of the last ten years in Amsterdam. No lights were used in any of those shootings.”

Van der Linden said the Police Academy still trains special forces in the advanced use of lights in combination with firearms, while regular officers receive basic training only. “Most of the 40+ trainers at the Police Academy are combat specialists, and they train students in a wide variety of techniques and equipment. Our officers do have to fight a lot in hand-to-hand, and for this the strobe device is a big help.”

He says the use of flashlights to gain a tactical advantage over unarmed suspects has been recognised for at least 30 years, but in the last decade the Dutch police noticed that major advances were being made in flashlight technology and decided to investigate whether these could be applied to their work. Their initiative began seven years ago, with a long-term study using police officers and students as guinea pigs. Participants included regular cops, traffic officers, detectives, arrest squads, K9 units, horse units and others. The study also explored the possibility of eye damage or other health problems. 

The research method was essentially trial-and-error, testing to see what worked and what didn’t, and adapting their methods and equipment as they went along. One of the research tools was a questionnaire that every student had to fill out after training. Another was to observe the results of exercises using tactical lights during training sessions. Ninety percent of their training did not involve weapons, although students are trained to use tactical lights in association with firearms.

In essence their findings are that, to overcome an aggressive opponent, a strobe is a far better choice than a constant beam of the same intensity. However, it is critical that the strobe is at the right frequency – too slow, and an opponent is able to move without being observed; too high and the strobe is more annoying than disorienting. The ideal frequency was found to be between 18hz and 20hz, where the strobe is extremely disorientating but an opponent cannot move without detection. 

Another consideration was beam profile – a narrow beam, concentrating all the intensity of the light into the eyes of an opponent, was found to be the most effective. With an extremely bright strobe in a subject’s eyes, the police found they could approach to within arm’s length, without him being aware how close they were.

Van der Linden points out that floodlights, with wide beams, are for searching, and should not be used in a tactical situation since they can illuminate the police as easily as a subject. Also, the dispersal of the light over a wide area greatly diminishes brightness, which is crucial in tactical situations.

What it does

Subjects (in the form of police students) found it impossible to estimate distances while they were exposed to a very bright strobe – they could not tell if the source of the light was one metre or three metres away. “That is a very worthy tactical advantage when approaching an aggressive person,” van der Linden observes.

Many times subjects brought their arms up, either as an involuntary “flinch movement” or to shield their eyes, presented an arresting officer with an opening to grab their arm and subdue them. In spite of themselves, subjects often closed their eyes, making it even easier to overcome them.

The police trainers found that aggressive drunks were the most affected by an intense strobe, often stumbling or falling instead of attacking. “I've also seen a drunk guy swing wildly when he got hit with a strobe in the face, although he wasn't very close as he was swinging blind with his eyes closed.

"I can tell you that in a darker environment, even a flash from a light with more than 500 lumens leaves a big blind spot in their vision for several minutes. The tactical strobe is very effective at disorienting intoxicated individuals. I've heard of several belligerent drunks who immediately doubled over and started throwing up, after being strobed for several seconds.”

Tactical strobes also proved invaluable in confined spaces, such as indoors or on buses or trains, and the police have even found strobes useful in subduing people with mental disorders. “In Holland we train to hold back on pepper spray when dealing with these sorts of persons,” he explains. “They are more patients then criminals – so blinding them for a short period is better than a spray – it does them no harm, and there’s less chance of getting sprayed ourselves.”

When used in conjunction with firearms, officers found they could fire as effectively when using a 20Hz strobe as a regular light, but gunmen on the receiving end of the strobe found it very hard to shoot back effectively. “To sight your target, you must look directly into that strobe, which is extremely difficult.” Van der Linden wryly explains that such exercises are done with non-lethal training ammo called simunition. “It still hurts, though!”

The ideal light

Having identified the critical features for an effective tactical light, the Dutch police found that it did not exist in the marketplace. “The makers of so-called ‘tactical lights’ have built what they THINK is good for us, not what we need. So we had to design it ourselves.” Even so, when they approached a number of manufacturers, they found that only one took up the challenge.

The features of their light, which is still in the testing phase, include:

  • One switch only, on the tail. Many flashlights – including those that are marketed as “tactical” – have two or more switches, often requiring combinations of clicks, or twisting the head, to reach full power or trigger a strobe. Van der Linden says this is not acceptable because there’s a high probability of doing the wrong thing under stress. “What you can do in these moments is just press your thumb, and hold it or release it.”
  • When turned on the light always starts with the strobe, at full power. And, critically, this feature cannot be changed: “If we issue a light that is programmable, 80% [of police officers] will program it for more practical use. Within a few weeks their tactical lights will start up in twenty lumen [low] mode for writing tickets, and they will throw away that small tactical advantage. We made a tactical device that can be changed to a normal light within two seconds, but only if you have no stress and no need for tactics. When you finish writing your ticket and put your light back in the holster, it returns to the tactical device it is designed to be.”
  • The flashlight must be capable of single-handed operation, instantly accessible using the non-weapon (and clumsier!) hand. The flashlight is carried pointing downwards, in a specially-designed holster, and is attached to the belt or holster with a short spiral cord that prevents it from being lost in stressful situations. However, the cord must not be strong enough to be used to strangle a person.
  • The emitter must be capable of at least 250 lumens, in a narrow beam and with a runtime of at least two hours. In addition, the flashlight has to be small and light enough to be carried always – a maximum of 140mm length, with a 32mm head and weighing no more than 400 grams including battery and holster. “Technically this is a challenge,” admits van der Linden. “When it’s too large, cops tend to leave it in the car or at the station – and there’s nothing tactical about a light that you don’t have with you.” They found a 32mm head with an XP-G emitter to be optimal. The XM-L emitter was very good, but with a 32cm reflector had too much spill. The XP-G had fewer lumens, but less spill and better power management – so the lux measured on the target was almost the same as from an XM-L in the same size head.
  • It must be 100% reliable under the most adverse circumstances, including being dropped, submerged, and used in hand-to-hand combat. However, at the same time it must be cost-effective – delivering full performance on a single rechargeable 18650 Li-Ion battery. “We’ve worked with these batteries for the last three years and have had zero defects or problems with them.”
  • It must not have a “strike bezel” or sharp rim. In Holland there are strict regulations about what weapons a police officer may carry, and a metal cylinder with a sharpened end, capable of ripping the flesh of someone during an arrest, is NOT on the list! “A special hardened point to shatter a car window is another thing, but that’s already on my key chain.”

Yes, but…

Van der Linden is quick to point out that it takes practice to use the tactical advantages of a dedicated tactical light, and the guidance of a trainer who is informed of the latest techniques. “Even most police trainers are not up to date in this knowledge,” he observes. “That’s normal – we all have our specialties. You can't know all.”

He also hinted that the Police Academy were developing lights for tactical purposes within other specialised departments, other than regular law-enforcement officers. “I can’t elaborate on that, but it is a work in progress.”

Finally, he warned that blinding lights could be dangerous when used inappropriately in traffic or when high velocity is involved.

Responding to the forum, an American policeman said the most common use of flashlights was at traffic blocks, where “a very bright light in the face tends to temporarily blind folks and even stun them… and allows for a quick visual inspection of the vehicle interior. There's little danger of the driver being night-blinded as they drive off, since the duration of a routine traffic stop will give their eyes enough time to recover. Even against drunk or belligerent suspects, the bright light being suddenly shone in their face/eyes is usually enough to disorient them.”

Van der Linden responded that the Dutch police never use a tactical light to blind a motorist just to check his license or his car. “Never, period!” They only used them to gain the upper hand over an aggressor. Other contributors said van der Linden’s experience mirrored their own, for example: “The strobe has a more disorienting effect compared to a similar lumen constant light, though it is by no means a ‘fight stopper’. It does provide a tactical option and can help in attaining/maintaining an advantage.”

An emergency-room nurse said he had found a strobe to be very helpful – and most effective at 15hz. “We have patients that are psychotic, irrational and combative on most days. The light has stopped a number of patients charging to attack or in the midst of losing control. With the light in their eyes, they can't coordinate a good punch and it usually causes them to close their eyes and shield their eyes… and we can safely de-escalate without restraining them or risking injury to the patients or staff.” Interestingly, the nurse said he found no benefit to using the light on patients who were lying down.

Turning to the prevailing belief that someone will have an epileptic seizure when exposed to a strobe, the nurse said some doctors had requested that he refrain from using the light. However, patients were statistically at higher risk of injury from a “take down” or from being injected with a tranquilliser – or even from being in the hospital for 24 hours.

Van der Linden responded that, in many years of testing strobes and training around 1,500 officers, they had never witnessed an epileptic reaction of any kind. He said Dutch police were trained to subdue mental patients: “The chance of risk with strobe is by far less then about any other means to control aggressive patients.”

* Compiled from this thread on Candlepowerforums, and kindly approved by Mr van der Linden.