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What influences the Taser's effectiveness? Police explain after recent high-profile incidents

What influences the Taser's effectiveness? Police explain after recent high-profile incidents

Videos on social media showed police officers pointing their Tasers at a man in the Beach Road incident.

SINGAPORE: On Apr 14, videos circulating on social media showed two police officers pointing their Taser at a man inside a Beach Road area restaurant. The man's arms were outstretched, his wrists bloodied.

Other videos painted more horrific scenes. The man was earlier seen outdoors slashing a woman with a chopper, leaving her bleeding profusely. People desperately hurled chairs, dustbins and standees at him, hoping to fend him off.

Back in the restaurant, a distinct crack is heard. The Taser had been fired. The man instantly fell to the ground and officers jumped in for the arrest.

The man was later identified as Cheng Guoyuan, 46. He has since been charged with the attempted murder of a 41-year-old woman believed to be his wife.

The Singapore Police Force currently uses the Taser X26P, produced by Axon Enterprise. (Photo: Axon)

But Tasers, designed to deliver electric charges to temporarily incapacitate a subject, do not always work like in the Beach Road case.

A Taser's effectiveness ultimately depends on where its probes land on a body, the Singapore Police Force (SPF) said on Thursday (Apr 21) in response to queries from CNA.

One factor is the spread, or distance, between the two probes, a police spokesperson said. Sufficient distance between the probes ensures electricity flows through enough muscle to freeze a subject.

In a dynamic situation where the officer or subject is in motion, one or both probes may miss, not embed properly, or get dislodged even if embedded properly earlier, the spokesperson said.

"The attire the subject is in, the distance between the subject and the officer, and the degree of movement by the subject may affect the successful deployment of the Taser," the spokesperson added.

On Mar 23, police shot dead a 64-year-old man at a Bendemeer block when he continued advancing towards officers with a knife despite being hit three times with a Taser.

A police spokesperson said then that Tasers are not always able to fully incapacitate a person and that the effect varies from person to person.

"Police officers are trained in the use of force, which include the use of less-lethal force options such as Tasers, to de-escalate and contain a myriad of situations during their day-to-day operations," SPF said on Thursday.

"They are required to consider the proportionality of the force to be applied vis-a-vis the perceived threat posed by a subject, the safety of members of the public and fellow officers, as well as the safety of the subject on which force is to be applied."


SPF uses the Taser X26P, produced by Axon Enterprise and first released in 2013. The Arizona-based company – named Taser International until 2017 – develops technology and weapons for military, law enforcement and civilians.

When a Taser is fired from a distance, it discharges darts connected by copper wires at a subject. These darts pierce muscle and the probes on their tips deliver pulses of electricity.

"When both probes land on the subject’s body, a surge of voltage is delivered to override the sensory and motor nervous systems in the area and cause an uncontrollable contraction of muscles or neuromuscular incapacitation," the police spokesperson said.

"This may result in temporary physical incapacitation of the subject."

While media reports tend to highlight the 50,000 volts that power a Taser, a Reuters report in 2017 said this voltage never reaches the subject. Instead, what matters is the delivered charge, measured in microcoulombs.

The X26P delivers a maximum charge of about 72 microcoulombs per pulse, about half that of the original X26. The X26's takedown power of 135 microcoulombs comes with higher cardiac risk, a Reuters examination of scientific literature and corporate, court and patent records found.

The Taser X26P with its laser, probes and copper wires visible during discharge. (Photo: Axon)

SPF said on its website that it brought in the X26 in 2005 to help officers "subdue non-compliant persons in a non-lethal manner". SPF told CNA it started using Tasers in 2008, and that their deployment by officers "have not resulted in cardiac arrest or death".

"In the unlikely event of a cardiac arrest, officers are first-aid-trained to manage persons suffering from a cardiac arrest prior to the arrival of emergency medical services," the spokesperson said.

"Officers are trained to avoid situations, such as a potential fall hazard, where the subject may be at risk of serious injury or death if the Taser is applied."


When a Taser is fired, its darts spread apart from each other as they fly through the air towards a subject, an APM Reports article in 2019 said. This means the range at which a Taser can effectively be used depends on how quickly the probes spread apart.

In its Taser user manuals, Axon has recommended a 30.5cm-spread between the probes for electricity to flow through enough muscle to reliably take down a subject. Greater probe spread increases effectiveness.

The X26P manual said its bottom probe impacts at an 8 degree angle from the top probe, meaning the Taser needs to be 2.1m from the subject to achieve a 30.5cm-spread between the probes.

An Axon spokesperson told CNA that a Taser's ability to create neuromuscular incapacitation depends on whether certain conditions are met, including a completed circuit and sufficient muscle mass from probe spread.

"If there is no completed circuit (one or two missed probes) or insufficient muscle mass, there is no potential for neuromuscular incapacitation without taking additional steps," the spokesperson said.


SPF did not say how a subject's condition, like whether they are drunk or high on drugs, might influence a Taser's effectiveness, but the Axon spokesperson said it could still work.

The man who was shot dead in the Bendemeer incident was a known drug offender and had drug apparatus in his unit, SPF had said.

"Unlike other less-lethal use of force tools, Taser energy weapons do not rely on pain compliance," the Axon spokesperson said.

"Rather, they are designed to affect a person’s involuntary muscle control and, as such, can be effective on individuals under the influence of drugs or alcohol."

Despite that, a 2021 New York Times report quoted an expert who said Tasers are ineffective on those who are high on mind-altering drugs. The effectiveness of less-lethal methods also depend on a subject's physical stature and how amped up they might be on adrenaline.

SPF said it "closely" monitors the track record of the X26P, pointing out that it is used by many other major police departments in the world.

The APM Reports article compared the Taser effectiveness rate in 12 US police departments – including New York and Los Angeles – and found that they range between 57.1 per cent and 79.5 per cent. Seven of the 12 departments had effectiveness rates below 70 per cent.

"If the Taser fails, officers are trained to utilise other use of force options, including the use of the baton or firearm depending on their assessment of the situation," SPF said.


SPF said it continuously reviews the training, procedures and equipment of its officers to ensure they can execute their duties "effectively and safely in line with the security climate".

Axon said its latest Taser 7 model, released in 2018, comes with a 12-degree probe spread so it can be optimally deployed from a shorter distance of 1.2m apart, "where most encounters involving an energy weapon occur".

"This creates an increased probe spread which greatly improves incapacitation rates," the spokesperson said.

Beyond that, the company said its Taser 7 has an improved probe design that breaks away from the dart upon impact to prevent recoil. The probes also shoot out faster, allowing for better and more accurate connection with the subject.

When it comes to SPF training, the Home Team Science and Technology Agency (HTX) has developed a mobile taser training target, or a remote-controlled human-looking robot on wheels.

The robot uses advanced computer vision technology to detect the landing points of taser probes on the training target. It can also project audio to reflect hits and misses, and realistically simulate the physical engagement between officer and subject.

"Currently, police training requires a role player to don a padded suit and act as the suspect during taser scenario-based training. This requires additional manpower and may cause physical injury," HTX said on its website.

SPF officers training with the mobile taser training target. (Photo: Home Team Academy)

Some SPF full-time national servicemen (NSF) also get to briefly feel a Taser's charge during training. This is done using the Taser's drive mode, in which the probes are driven directly into the body at close range instead of fired from a distance.

One former NSF, speaking on the condition of anonymity, told CNA that it was "not physically painful", although he felt "completely immobilised". He did not give further details.

Axon said it provides training recommendations for its Tasers, including training on factors that contribute to effectiveness such as sufficient muscle mass and probe spread. 

"Axon also recommends annual certification training, including scenario-based training under stress similar to what an officer may experience in the field to help ensure appropriate and effective deployments," the spokesperson added.

Source: CNA/hz(cy)


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