Riot control measures are used by

law enforcement Law enforcement is the activity of some members of government who act in an organized manner to enforce the law by discovering, deterring, rehabilitating, or punishing people who violate the rules and norms governing that society. The term ...

military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...

paramilitary A paramilitary is an organization whose structure, tactics, training, subculture, and (often) function are similar to those of a professional military, but is not part of a country's official or legitimate armed forces. Paramilitary units carr ...

or security forces to

control Control may refer to: Basic meanings Economics and business * Control (management), an element of management * Control, an element of management accounting * Comptroller (or controller), a senior financial officer in an organization * Controlli ...

, disperse, and

arrest An arrest is the act of apprehending and taking a person into custody (legal protection or control), usually because the person has been suspected of or observed committing a crime. After being taken into custody, the person can be questi ...

people who are involved in a

riot A riot is a form of civil disorder commonly characterized by a group lashing out in a violent public disturbance against authority, property, or people. Riots typically involve destruction of property, public or private. The property targete ...

, unlawful demonstration or unlawful

protest A protest (also called a demonstration, remonstration or remonstrance) is a public expression of objection, disapproval or dissent towards an idea or action, typically a political one. Protests can be thought of as acts of cooper ...

. If a riot is spontaneous and irrational, actions which cause people to stop and think for a moment (e.g. loud noises or issuing instructions in a calm tone) can be enough to stop it. However, these methods usually fail when there is severe anger with a legitimate cause, or the riot was planned or organized. Riot control personnel have long used

less lethal weapon Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...

s such as batons and whips to disperse crowds and detain rioters. Since the 1980s, riot control officers have also used

tear gas Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In ...

pepper spray Pepper spray, oleoresin capsicum spray, OC spray, capsaicin spray, or capsicum spray is a lachrymatory agent (a compound that irritates the eyes to cause a burning sensation, pain, and temporary blindness) used in policing, riot control, ...

, rubber bullets,

stun grenades A stun grenade, also known as a flash grenade, flashbang, thunderflash, or sound bomb, is a less-lethal explosive device used to temporarily disorient an enemy's senses. Upon detonation, they produce a blinding flash of light and an extremely lou ...

, and electric

taser A taser is an electroshock weapon used to incapacitate people, allowing them to be approached and handled in an unresisting and thus safe manner. It is sold by Axon, formerly TASER International. It fires two small barbed darts intended t ...

s. In some cases, riot squads may also use

Long Range Acoustic Device A long-range acoustic device (LRAD) is an acoustic hailing device (AHD), sound cannon and sonic weapon developed by Genasys. It has been used as a method of crowd control, which has caused permanent hearing damage, having an extremely high ...

water cannon A water cannon is a device that shoots a high-velocity stream of water. Typically, a water cannon can deliver a large volume of water, often over dozens of meters. They are used in firefighting, large vehicle washing, riot control, and mining ...

s, armoured fighting vehicles,

aerial surveillance A surveillance aircraft is an aircraft used for surveillance. They are operated by military forces and other government agencies in roles such as intelligence gathering, battlefield surveillance, airspace surveillance, reconnaissance, observa ...

, police dogs or

mounted police Mounted police are police who patrol on horseback or camelback. Their day-to-day function is typically picturesque or ceremonial, but they are also employed in crowd control because of their mobile mass and height advantage and increasingly in t ...

on horses. Persons performing riot control typically wear protective equipment such as riot helmets, face visors,

body armor Body armor, also known as body armour, personal armor or armour, or a suit or coat of armor, is protective clothing designed to absorb or deflect physical attacks. Historically used to protect military personnel, today it is also used by variou ...

(vests, neck protectors, knee pads, etc.),

gas mask A gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas mas ...

s and riot shields. There have been cases where lethal weapons are used to violently suppress a protest or riot, as in the Boston Massacre, Haymarket Massacre, Banana Massacre,

Hungarian Revolution of 1956 The Hungarian Revolution of 1956 (23 October – 10 November 1956; hu, 1956-os forradalom), also known as the Hungarian Uprising, was a countrywide revolution against the government of the Hungarian People's Republic (1949–1989) and the Hunga ...

Kent State Shootings The Kent State shootings, also known as the May 4 massacre and the Kent State massacre,"These would be the first of many probes into what soon became known as the Kent State Massacre. Like the Boston Massacre almost exactly two hundred years bef ...

, Soweto Uprising, Mendiola Massacre, Bloody Sunday (1905), Ponce massacre, Bloody Sunday (1972), 1989 Tiananmen Square protests, 2017 Venezuelan protests,

2018–2019 Gaza border protests The 2018–2019 Gaza border protests, by the organiser called the Great March of Return ( ar, مسیرة العودة الكبرى, Masīra al-ʿawda al-kubrā), were a series of demonstrations held each Friday in the Gaza Strip near the Gaz ...

Citizenship Amendment Act protests The Citizenship Amendment Act (Bill) protests, also known as the CAA Protest, CAB Protest or CAA and NRC protests, occurred after the Citizenship Amendment Act (CAA) was enacted by the Government of India on 12 December 2019. The move sparked ...

2022 Sri Lankan protests The 2022 Sri Lankan protests ( si, අරගලය, translit=Aragalaya, lit=Struggle), are mass protests that began in March 2022 against the government of Sri Lanka. The government has been criticized for mismanaging the Sri Lankan economy, ...

and Mahsa Amini protests.

History

Maintaining order during demonstrations and quenching riots has always been a challenge for governments and administrations. Until early in the 20th century, no dedicated force really existed in most countries and the traditional response when the regular police force proved inadequate was to call upon the army, often with disastrous results: either fraternization or use of excessive violence. The terminology arguably first arises in the Keystone Cops short " A Hash House Fraud" in 1915. In France, for example, several revolts were fueled by poor handling by the military. The National Gendarmerie created specialized "mobile" gendarmerie forces several times during the 19th century in times of trouble but these units were disbanded soon after the end of the troubles they had been tasked to handle and there was no permanent organization in place until it was finally decided in 1921 to create "Mobile Gendarmerie platoons" within the

Departmental Gendarmerie The Departmental Gendarmerie (french: Gendarmerie Départementale) is the territorial police branch of the French National Gendarmerie. The Departmental Gendarmerie has regular contact with the population and conducts local policing functions ...

. These platoons, either horse mounted or on foot were composed of 40 gendarmes each (60 in the Paris Region). In 1926, the platoons formed the "Garde Républicaine mobile" (mobile republican guard or GRM), which became a distinct branch of the Gendarmerie in 1927, the platoons becoming part of companies and legions. By 1940, the GRM was a force 21,000 strong, composed of 14 Légions, 54 company groups and 167 companies. Long the only large force specialized in maintaining or restoring law and order in France during demonstrations or riots, the GRM progressively developed the doctrine and skills needed in that role: exercise restraint, avoid confrontation as long as possible, always leave an "exit door" for the crowd, etc. In 1940, after the fall of France, the German authorities had the GRM disbanded but it was reinstated in 1944 and renamed Mobile Gendarmerie in 1954. Shanghai 1928 Bund Cenotaph

The first squad trained in modern techniques of riot control in Asia was formed in 1925 in colonial

Shanghai Shanghai (; , , Standard Chinese, Standard Mandarin pronunciation: ) is one of the four Direct-administered municipalities of China, direct-administered municipalities of the China, People's Republic of China (PRC). The city is located on the ...

as a response to the mismanaged riot of the

May Thirtieth Movement The May Thirtieth Movement () was a major labor and anti-imperialist movement during the middle-period of the Republic of China era. It began when the Shanghai Municipal Police opened fire on Chinese protesters in Shanghai's International Set ...

. New policing methods, including combat pistol shooting, hand to hand combat skills, and knife fight training, were pioneered by British Assistant Commissioner

William E. Fairbairn Lieutenant-Colonel William Ewart Fairbairn (; 28 February 1885 – 20 June 1960) was a British Royal Marine and police officer. He developed hand-to-hand combat methods for the Shanghai Police during the interwar period, as well as for the al ...

and officer Eric Anthony Sykes of the

Shanghai Municipal Police The Shanghai Municipal Police (SMP; ) was the police force of the Shanghai Municipal Council which governed the Shanghai International Settlement between 1854 and 1943, when the settlement was retroceded to Chinese control. Initially composed o ...

as a response to a staggering rise in armed crime in the

had become one of the world's most dangerous cities due to a breakdown in law and order in the country and the growth of

organised crime Organized crime (or organised crime) is a category of transnational, national, or local groupings of highly centralized enterprises run by criminals to engage in illegal activity, most commonly for profit. While organized crime is generally th ...

and the opium trade. Under Fairbairn, the SMP developed a myriad of riot control measures. These riot control techniques led to the introduction of Shanghai's "Reserve the first modern

SWAT In the United States, a SWAT team (special weapons and tactics, originally special weapons assault team) is a police tactical unit that uses specialized or military equipment and tactics. Although they were first created in the 1960s to ...

team. As a reserve unit, it was used to forcibly disband riots as well as to respond to high-level criminality like

kidnapping In criminal law, kidnapping is the unlawful confinement of a person against their will, often including transportation/asportation. The asportation and abduction element is typically but not necessarily conducted by means of force or fear: the p ...

s and

armed robberies Robbery is the crime of taking or attempting to take anything of value by force, threat of force, or by use of fear. According to common law, robbery is defined as taking the property of another, with the intent to permanently deprive the per ...

. The skills developed in Shanghai have been adopted and adapted by both international police forces and clandestine warfare units. William Fairbairn was again the central figure, not only leading the Reserve Unit, but teaching his methods around the world, including in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, and the colonial regimes of

Cyprus Cyprus ; tr, Kıbrıs (), officially the Republic of Cyprus,, , lit: Republic of Cyprus is an island country located south of the Anatolian Peninsula in the eastern Mediterranean Sea. Its continental position is disputed; while it is ...

and

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

Equipment

For protection, officers that are trained in police anti-riot schools performing riot control will often wear protective helmets and carry riot shields. These are designed to protect the wearer from those dangers that come from direct

melee A melee ( or , French: mêlée ) or pell-mell is disorganized hand-to-hand combat in battles fought at abnormally close range with little central control once it starts. In military aviation, a melee has been defined as " air battle in which ...

and hurled objects such as bottles and bricks. The gear frequently worn by riot control officers protects the entire body with no vulnerable spots to exploit. For example, the helmets worn by riot control officers have an additional outward-extending part that protects the back of the neck from assault. To provide even greater protection, the protective equipment often provides ballistic protection. If tear gas or other riot control agents are to be used,

s may also be worn. One of many additional concerns is to prevent people in the crowd from snatching officers'

side arms A sidearm is a weapon, usually a handgun, but sometimes a knife, dagger, sword, bayonet, or other melee weapon, which is worn on the body in a holster (in the case of a pistol or revolver) or sheath (in the case of a knife, dagger, sword, o ...

, which may be stolen or even used against the police. In a very heavy crowd, the officer may not be able to see who is responsible for snatching a weapon, and may not even notice that it has happened. For this reason, riot police may have

holster A handgun holster is a device used to hold or restrict the undesired movement of a handgun, most commonly in a location where it can be easily withdrawn for immediate use. Holsters are often attached to a belt or waistband, but they may be at ...

s with positive locking mechanisms or other extra means of retention, if their agencies can afford such tools. However, this can be a trade-off that increases the amount of time needed to draw the sidearm in an emergency. Alternately, riot police may not carry sidearms at all. The initial choice of

tactics Tactic(s) or Tactical may refer to: * Tactic (method), a conceptual action implemented as one or more specific tasks ** Military tactics, the disposition and maneuver of units on a particular sea or battlefield ** Chess tactics ** Political tact ...

determines the type of offensive equipment used. The base choice is between lethal (e.g. 12 gauge

shotgun A shotgun (also known as a scattergun, or historically as a fowling piece) is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which usually discharges numerous small pellet-like spherical sub- pr ...

) and

less-than-lethal weapon Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...

ry (e.g.

, plastic bullets,

s, batons, and other

incapacitant Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...

s). The decision is based on the perceived level of threat and the existing laws; in many countries it is illegal to use lethal force to control riots in all but the most extreme circumstances. Special riot hand weapons include the wooden or rubber baton; the African sjambok, a heavy leather or plastic whip, and the Indian lathi, a long cane with a blunt metal tip. Vehicle-mounted

s may serve to augment personal weapons. Some water cannons let police add

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

to mark rioters or tear gas to help disperse the crowds. In major unrest, police in armoured vehicles may be sent in following an initial subduing with firepower. Occasionally, police dogs, fire hoses, or

are deployed. File:Bastille 2007-05-06 anti Sarkozy 487645689 c9fce856e3 o.jpg, French gendarmes mobiles using tear gas File:Bastille 2007-05-06 anti Sarkozy 487623928 37656cd319 o.jpg, This

gendarme Wrong info! --> A gendarmerie () is a military force with law enforcement duties among the civilian population. The term ''gendarme'' () is derived from the medieval French expression ', which translates to "Man-at-arms, men-at-arms" ...

is shooting tear gas canisters using an Alsetex "Cougar" launcher File:Vietnamprotestors.jpg, U.S. Army troops are shown attempting to keep Vietnam War protesters from rioting in Washington, D.C., 1967. File:VOA Arrott - A View of Syria, Under Government Crackdown 07.jpg, Syrian riot control in

Damascus )), is an adjective which means "spacious". , motto = , image_flag = Flag of Damascus.svg , image_seal = Emblem of Damascus.svg , seal_type = Seal , map_caption = , ...

in 2012 File:Warszawa, Marsz Niepodległości 2011 05.jpg, Polish riot control police in

Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officiall ...

at the March of Independence in 2011 File:Riot police by the building of the Cabinet of Ministers.jpg, Defensive line of "Berkut" unitmen in riot gear by the Cabinet of Ministers building in

Kyiv Kyiv, also spelled Kiev, is the capital and most populous city of Ukraine. It is in north-central Ukraine along the Dnieper River. As of 1 January 2021, its population was 2,962,180, making Kyiv the seventh-most populous city in Europe. Ky ...

during 2013

Euromaidan Euromaidan (; uk, Євромайдан, translit=Yevromaidan, lit=Euro Square, ), or the Maidan Uprising, was a wave of demonstrations and civil unrest in Ukraine, which began on 21 November 2013 with large protests in Maidan Nezalezhno ...

protests. File:Policiais Manifestacoes 20170209.jpg, Riot control group of Rio de Janeiro Police in confrontation with protesters in the historical center of the city. File:Reparto Celere.jpg, Italian ''Celerini'' in the 1950s. File:Police Protesters Clash after Eid Prayers in Kashmir 2 Sept 2017 29.jpg, Pellet shotguns have been used by Indian security forces for crowd control in Jammu and Kashmir against stone pelting mobs. File:Water Cannon used on İstiklâl Caddesi near Taksim Square - Gezi Park, İstanbul - Flickr - Alan Hilditch.jpg, Intervention vehicle for social events that interfered with demonstrators in Gezi Park (

Istanbul ) , postal_code_type = Postal code , postal_code = 34000 to 34990 , area_code = +90 212 (European side) +90 216 (Asian side) , registration_plate = 34 , blank_name_sec2 = GeoTLD , blank_i ...

) in 2013

Riot control agent (RCA)

Riot control agents (sometimes called RCAs) are “ non-lethal lachrymatory agents “ used for riot control. Most commonly used riot control agents are

and various kinds of tear gas. These chemicals disperse a crowd that could be protesting or

ing, or to clear a building. They can rapidly produce sensory irritation or disabling physical effects which usually disappear within 15 minutes (for tear gas) and up to 2 hours (for pepper spray) following termination of exposure. They can also be used for

chemical warfare Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military a ...

defense training, although their use in warfare itself is a violation of Article I.5 of the

Chemical Weapons Convention The Chemical Weapons Convention (CWC), officially the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, is an arms control treaty administered by the Organisation for ...

. Article II.9 of the CWC specifically authorizes their use for domestic law enforcement.

Pepper spray

The active ingredient in pepper-spray is

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) ( or ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a chemical irritant for mammals, including humans, and produces a sensation of burnin ...

, which is a chemical derived from the fruit of plants in the ''

Capsicum ''Capsicum'' () is a genus of flowering plants in the nightshade family Solanaceae, native to the Americas, cultivated worldwide for their chili pepper or bell pepper fruit. Etymology and names The generic name may come from Latin , me ...

'' genus, including chilies. Desmethyldihydrocapsaicin, a synthetic analogue of capsaicin also known as pelargonic acid vanillylamide or PAVA, is used in another version of pepper spray known as PAVA spray and used in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...

. Another synthetic counterpart of pepper spray, pelargonic acid morpholide, was developed and is widely used in

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

. Its effectiveness compared to natural pepper spray is uncertain and it reportedly has caused some injuries. When undesirables threaten an area, such as a riot after a soccer game, riot police are called in to subdue them. In these situations, the police may use pepper spray, or water cannons to neutralize the threat. Pepper spray typically comes in canisters, which are often small enough to be carried or concealed in a pocket or purse. Pepper spray can also be bought concealed in items such as rings. There are also pepper spray projectiles available, which can be fired from a

paintball gun A paintball marker, also known as a paintball gun, paint gun, or simply marker, is an air gun used in the shooting sport of paintball, and the main piece of paintball equipment. Paintball markers use compressed gas, such as carbon dioxide (CO ...

. Having been used for years against demonstrators, it is increasingly being used by police in routine interventions.

Tear gas

Tear gas is a non-specific term for any chemical that is used to temporarily incapacitate through irritation of eyes and/or respiratory system. It is used as a hand-held spray or can be fired in canisters that heat up spewing out an

aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogen ...

cloud at a steady rate. Whilst the use of tear gas in warfare is prohibited by various international treatiese.g. the Geneva Protocol of 1925: 'Prohibited the use of "asphyxiating gas, or any other kind of gas, liquids, substances or similar materials"' that most states have signed, however police and private self-defense use is not banned in an international manner. Popular tear gases include the eye irritants ortho-chlorobenzylidene-malononitrile (CS gas), chloroacetophenone (CN gas), and dibenz (b,f)-1,4-oxazepine (CR gas). Among a long list of substances, these three have become of greater importance than the others because of their effectiveness and low risks when used. Today, CS has largely replaced CN as the most widely used tear gas internationally.

Decontamination

At room temperature, tear gases are white solids. They are stable when heated and have low

vapor pressure Vapor pressure (or vapour pressure in English-speaking countries other than the US; see spelling differences) or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed pha ...

. Consequently, they are usually dispersed as

s. All of them have low

solubility In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubi ...

in water but can be dissolved in several organic solvents.

Hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

of CN is very slow in a water solution, especially if

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

is added. CS is rapidly hydrolyzed in water solution (half-life at pH 7 is about 15 min. at room temperature) and extremely rapid when alkali is added (half-life at pH 9 is about 1 min.). CR is hydrolyzed only to a negligible extent in water solution. CN and CR are, thus, difficult to decompose under practical conditions, whereas CS can easily be inactivated by means of a water solution. Skin is suitably decontaminated of CS and CN gas by thorough washing with soap and water. CS is then decomposed, whereas CN is only removed via soap and water. The effects of CR gas are greatly increased by water, causing any attempt to DECON CR via soap and water to increase the severity and duration of the effects. When decontamination of CR is attempted with soap and water the effects of CR can last up to 48 hours Decontamination of material after contamination with CR gas is not possible for up to 45 days. CS can be decontaminated l with a 5–10 percent soda solution or 2 percent alkaline solution. If this type of decontamination cannot be accomplished (e.g., contaminated rooms and furniture), then the only other means is by intensive air exchange—preferably with hot air. Exposed streets and sidewalks will have toxic and irritating CS powder that will be stirred into the air by traffic and pedestrians long after the cloud has dissipated, and should be washed away with water. In contrast to human beings, domesticated animals generally have lower sensitivity to tear gases. Dogs and horses can therefore be used by police for riot control even when tear gas is used.

Dispensing large quantities

Backpack dispensers for riot control agents, when the intent is to use a larger quantity than possible with grenades, are one type of device used by organizations that might, for example, need to cover a prison yard. Dispensers are also made for attachment to helicopters; see CBU-19.

Tactics

The front-line officers in a riot control are often fully armored and carry weapons such as batons, designed to be in direct contact with the crowd. These officers subdue rioters and subsequently allow the less heavily armoured, more mobile officers to make arrests where it is deemed necessary. In face of a greater threat, the riot police will be backed up with other officers equipped with riot guns to fire

, rubber bullets, plastic bullets or "beanbag" rounds. As a less aggressive step,

may first be sent into the crowd. The might and height offered by the

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

are combined with its training, allowing an officer to more safely infiltrate a crowd. Usually, when front-facing a riot, officers slowly walk in a line parallel to the riot's front, extending to both its ends, as they noisily and simultaneously march and beat their shields with their batons, to cause fear and psychological effects on the crowd. ASEM-Demonstration Hamburg 006

Since the advent of artillery, straight roads have been of notable importance in city defense and control. Upon coming to power,

Napoleon III Napoleon III (Charles Louis Napoléon Bonaparte; 20 April 18089 January 1873) was the first President of France (as Louis-Napoléon Bonaparte) from 1848 to 1852 and the last monarch of France as Emperor of the French from 1852 to 1870. A neph ...

built great avenues, referred to as anti-riot streets, into the troublesome quarters of Paris. The wide straight roads also allowed for cavalry charges to subdue rioters. In the United Kingdom, usually when large demonstrations take place that are deemed unstable, the

territorial police force A territorial police force is a police service that is responsible for an area defined by sub-national boundaries, distinguished from other police services which deal with the entire country or a type of crime. In countries organized as federations, ...

responsible for the demonstration in that area will usually deploy

Police Support Unit The Police Support Unit, also known by their nickname of the Black Boots, is a paramilitary wing of the Zimbabwe Republic Police. They were founded as a native police force but later developed into a counter-insurgency unit of the British South A ...

personnel who are trained in riot tactics, along with normal divisional officers. If the demonstration turns violent, police will seal roads and other exits to contain protesters in a single area (known as kettling) to prevent widespread damage and wait until the protesters tire. These tactics were seen during the

2009 G-20 London summit protests The 2009 G20 London summit protests occurred in the days around the 2 April 2009 G20 London summit. The summit was the focus of protests from a number of groups over various long-standing and topical issues. These ranged from disquiet over econ ...

and the 2010 student protests in London. Tear gas and other more offensive tactics are used as a last resort. Throughout police will be videoing or photographing protesters for future arrests, " snatch squad" tactics might also be used where several police officers, usually in protective riot gear, rush forwards, occasionally in flying wedge formation to break through the front of a crowd, with the objective of snatching one or more individuals from a riot that are attempting to control the demonstration at which they are present; the target may be a leader or a speaker, or someone who seems to be leading the crowd. This tactic was used in the

2011 England Riots The 2011 England riots, more widely known as the London riots, were a series of riots between 6 and 11 August 2011. Thousands of people rioted in cities and towns across England, which saw looting, arson, as well as mass deployment of police an ...

, most notably by Greater Manchester Police who deployed this tactic in Manchester city centre on 9 August 2011. A more straightforward tactic police may use is a baton charge which involves police officers charging at a crowd of people with batons and in some cases, riot shields. They run at the crowd hitting people with their batons, and in some situations use riot shields to push them away. Baton charging is designed to cause the maximum amount of

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

, in the hope that they would be compelled to move away from the scene, dispersing the crowd.

Research

Long Range Acoustic Device 500X in New York City

Research into weapons that are more effective for riot control continues. Netguns are non-lethal weapons designed to fire a net which entangles the target. Netguns have a long history of being used to capture wildlife, without injury, for research purposes. A netgun is currently in development for non-lethal riot control. Pepper-spray projectile launchers are

projectile A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found i ...

weapon A weapon, arm or armament is any implement or device that can be used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime, law enforcement, s ...

s that launch a fragile ball which breaks upon impact and releases an irritant powder called PAVA (capsaicin II) pepper. The launchers are often slightly modified .68

caliber In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matc ...

paintball guns.

Stink bomb A stink bomb, sometimes called a stinkpot, is a device designed to create an unpleasant smell. They range in effectiveness from being used as simple pranks to military grade malodorants or riot control chemical agents. History A stink bomb ...

s are devices designed to create an extremely unpleasant smell for riot control and area denial purposes. Stink bombs are believed to be less dangerous than other riot control chemicals, since they are effective at low concentrations.

Sticky foam Sticky foam is a type of less-lethal weapon, consisting of various extremely tacky and/or tenacious materials carried in compressed form with a propellant and used to block, entangle, and impair individuals. A National Institute of Justice-funded ...

weapons are being tested, which cover and immobilize rioters with a gooey foam.

Low frequency Low frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre wave. LF radio waves e ...

sound cannon A long-range acoustic device (LRAD) is an acoustic hailing device (AHD), sound cannon and sonic weapon developed by Genasys. It has been used as a method of crowd control, which has caused permanent hearing damage, having an extremely hig ...

s are weapons of various types that use sound to injure or incapacitate subjects using a focused beam of

sound In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by ...

or infrasound.

Active denial system The Active Denial System (ADS) is a non-lethal directed-energy weapon developed by the U.S. military, designed for area denial, perimeter security and crowd control. Informally, the weapon is also called the heat ray since it works by heating th ...

s (ADS) are a non-lethal, directed-energy weapon developed by the U.S. military. The ADS directs

electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...

, specifically, high-frequency microwave radiation, at a frequency of 95 GHz, which causes the water in the upper epidermis to boil, stimulating a "burning" sensation in the nerve endings and generating intense pain. Dazzler lasers are directed-energy weapons that use intense light to cause temporary

blindness Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment� ...

History

Equipment

Riot control agent (RCA)

Pepper spray

Tear gas

Decontamination

Dispensing large quantities

Tactics

Research

See also

Riot control units

Weapons used in riot control

Notes

References

External links