Мотоциклетный шлем: история, безопасность и эффективность

Safety helmet used by motorcycle riders

A motorcycle helmet is a type of helmet used by motorcycle riders. Motorcycle helmets contribute to motorcycle safety by protecting the rider's head in the event of an impact. They reduce the risk of head injury by 69% and the risk of death by 42%. Their use is required by law in many countries. Motorcycle helmets consist of a polystyrene foam inner shell that absorbs the shock of an impact, and a protective plastic outer layer. Several variations exist, notably helmets that cover the chin area and helmets that do not. Some helmets provide additional conveniences, such as ventilation, face shields, sun visors, ear protection or intercom.

The origins of the crash helmet date back to the Brooklands race track in early 1914, when a medical officer, Dr. Eric Gardner, noticed he was seeing a motor cyclist with head injuries about every two weeks. He got a Mr. Moss of Bethnal Green to make canvas and shellac helmets stiff enough to stand a heavy blow and smooth enough to glance off any projections it encountered. He presented the design to the Auto Cycle Union where it was initially condemned, but later converted to the idea and made them compulsory for the 1914 Isle of Man TT races, although there was resistance from riders. Gardner took 94 of these helmets with him to the Isle of Man, and one rider who hit a gate with a glancing blow was saved by the helmet. Dr. Gardner received a letter later from the Isle of Man medical officer stating that after the T. T. they normally had "several interesting concussion cases" but that in 1914 there were none. In May 1935, T. E. Lawrence (known as Lawrence of Arabia) had a crash on a Brough Superior SS100 on a narrow road near his cottage near Wareham. The accident occurred because a dip in the road obstructed his view of two boys on bicycles. Swerving to avoid them, Lawrence lost control and was thrown over the handlebars. He was not wearing a helmet, and suffered serious head injuries which left him in a coma; he died after six days in the hospital. One of the doctors attending him was Hugh Cairns, a neurosurgeon, who after Lawrence's death began a long study of what he saw as the unnecessary loss of life by motorcycle despatch riders through head injuries. Cairns' research led to the increased use of crash helmets by both military and civilian motorcyclists and the British Army making helmets compulsory for its riders in November 1941. In the USSR, helmets for motorcyclists became mandatory starting in November 1967. Protective helmets for all motorcyclists and passengers became mandatory since January 1973.

A 2008 systematic study showed that helmets reduce the risk of head injury by around 69% and the risk of death by around 42%. Although it was once speculated that wearing a motorcycle helmet increased neck and spinal injuries in a crash, recent evidence has shown the opposite to be the case: helmets protect against cervical spine injury. A study that is often cited when advancing the argument that helmets might increase the incidence of neck and spinal injuries dates back to the mid 1980s and "used flawed statistical reasoning".

A full face helmet covers the entire head, with a rear that covers the base of the skull, and a protective section over the front of the chin. Such helmets have an open cutout in a band across the eyes and nose, and often include a clear or tinted transparent plastic face shield, known as a visor, that generally swivels up and down to allow access to the face. Many full face helmets include vents to increase the airflow to the rider. The significant attraction of these helmets is their protectiveness. Some wearers dislike the increased heat, sense of isolation, lack of wind, and reduced hearing of such helmets. Full face helmets intended for off road or motocross use sometimes omit the face shield, but extend the visor and chin portions to increase ventilation, since riding off road is a very strenuous activity. Studies have shown that full face helmets offer the most protection to motorcycle riders because 35% of all crashes showed major impact on the chin bar area. Wearing a helmet with less coverage eliminates that protection — the less coverage the helmet offers, the less protection for the rider.

The motocross and off road helmet has clearly elongated chin and visor portions, a chin bar, and partially open face to give the rider extra protection while wearing goggles and to allow the unhindered flow of air during the physical exertion typical of this type of riding. The visor allows the rider to dip his or her head and provide further protection from flying debris during off road riding. It also serves the obvious purpose of shielding the wearer's eyes from the sun. Originally, off road helmets did not include a chin bar, with riders using helmets very similar to modern open face street helmets, and using a face mask to fend off dirt and debris from the nose and mouth. Modern off road helmets include a (typically angular, rather than round) chin bar to provide some facial impact protection in addition to protection from flying dirt and debris. When properly combined with goggles, the result provides most of the same protective features of full face street helmets.

A hybrid between full face and open face helmets for street use is the modular or "flip up" helmet, also sometimes termed "convertible" or "flip face". When fully assembled and closed, they resemble full face helmets by bearing a chin bar for absorbing face impacts. Its chin bar may be pivoted upwards (or, in some cases, may be removed) by a special lever to allow access to most of the face, as in an open face helmet. The rider may thus eat, drink or have a conversation without unfastening the chinstrap and removing the helmet, making them popular among motor officers. It is also popular with people who use eyeglasses as it allows them to fit a helmet without removing their glasses. Many modular helmets are designed to be worn only in the closed position for riding, as the movable chin bar is designed as a convenience feature, useful while not actively riding. The curved shape of an open chin bar and face shield section can cause increased wind drag during riding, as air will not flow around an open modular helmet in the same way as a three quarters helmet. Since the chin bar section also protrudes further from the forehead than a three quarters visor, riding with the helmet in the open position may pose increased risk of neck injury in a crash. Some modular helmets are dual certified as full face and open face helmet. The chin bar of those helmets offer real protection and they can be used in the "open" position while riding. An example of such a helmet would be the BMW Motorrad System 6. As of 2008, there have not been wide scientific studies of modular helmets to assess how protective the pivoting or removable chin bars are. Observation and unofficial testing suggest that significantly greater protection exists beyond that for an open face helmet, and may be enough to pass full face helmet standardized tests, but the extent of protection is not fully established by all standards bodies. The DOT standard does not require chin bar testing. The Snell Memorial Foundation recently certified a flip up helmet for the first time. ECE 22.05 allows certification of modular helmets with or without chin bar tests, distinguished by P (protective lower face cover) and NP (non protective) suffixes to the certification number, and additional warning text for non certified chin bars.

The open face, or "three quarters", helmet covers the ears, cheeks, and back of the head, but lacks the lower chin bar of the full face helmet. Many offer snap on visors that may be used by the rider to reduce sunlight glare. An open face helmet provides the same rear protection as a full face helmet, but little protection to the face, even from non crash events. Bugs, dust, or even wind to the face and eyes can cause rider discomfort or injury. As a result, it is not uncommon (and in some U. S. states, is required by law) for riders to wear wrap around sunglasses or goggles to supplement eye protection with these helmets. Alternatively, many open face helmets include, or can be fitted with, a face shield, which is more effective in stopping flying insects from entering the helmet.

The half helmet, also referred to as a "Shorty" in the United States and "Pudding Basin" or TT helmet in the UK and popular with Rockers and road racers of the 1960s in the British Isles. It has essentially the same front design as an open face helmet but without a lowered rear in the shape of a bowl. The half helmet provides the minimum coverage generally allowed by law in the U. S., and British Standards 2001:1956. As with the open face, it is not uncommon to augment this helmet's eye protection through other means such as goggles. Because of their inferiority compared to other helmet styles, some Motorcycle Safety Foundations prohibit the use of half helmets now.

There are other types of headwear often called "beanies," "brain buckets", or "novelty helmets", a term which arose since they are uncertified and cannot legally be called motorcycle helmets in some jurisdictions. Such items are often smaller and lighter than helmets made to U. S. Department of Transportation (DOT) standards, and are unsuitable for crash protection because they lack the energy absorbing foam that protects the brain by allowing it to come to a gradual stop during an impact. A "novelty helmet" can protect the scalp against sunburn while riding and – if it stays on during a crash – might protect the scalp against abrasion, but it has no capability to protect the skull or brain from an impact.

Although black helmets are popular among motorcyclists, one study determined they offer the least visibility to motorists. Riders wearing a plain white helmet rather than a black one were associated with a 24% lower risk of suffering a motorcycle accident injury or death. This study also notes "Riders wearing high visibility clothing and white helmets are likely to be more safety conscious than other riders." Conversely, another study, the MAIDS report, did not back up the claims that helmet color makes any difference in accident frequency, and that in fact motorcycles painted white were actually over represented in the accident sample compared to the exposure data. While recognizing how much riders need to be seen, the MAIDS report documented that riders' clothing usually fails to do so, saying that "in 65.3% of all cases, the clothing made no contribution to the conspicuity of the rider or the PTW [powered two wheeler, i. e. motorcycle]. There were very few cases found in which the bright clothing of the PTW rider enhanced the PTW’s overall conspicuity (46 cases). There were more cases in which the use of dark clothing decreased the conspicuity of the rider and the PTW (120 cases)." The MAIDS report was unable to recommend specific items of clothing or colors to make riders better seen. Subsequently, however, research by Wali et al. (2019) found that: “Helmet color is also one of the factors that can increase or decrease rider conspicuity (Wells et al., 2004; Gershonetal., 2012 ). Usually, dark colored helmets (such as black) can decrease rider conspicuity whereas light colored helmets can increase conspicuity at times when the level of rider conspicuity can influence injury outcomes (as observed above in our findings and in relevant literature (Wells et al., 2004 )). Our analysis shows that black colored helmets are associated with a significant increase in the injury severity score (an increase of 4.25 units – see Table 5), whereas light colored helmets (such as silver or grey) are found associated with a significant decrease in the injury severity score (a decrease of 7.56units). These findings are in agreement with those of Wells et al. (2004) and are important and intuitive as usually dark colored helmets (such as black) can decrease rider conspicuity (especially at night) thus increasing the risk of injury (Wells et al., 2004). Interestingly, our analysis shows that white colored helmets are also associated with a significant increase in the injury severity score, given a crash (see Table 3). This finding may seem apparently unintuitive as white colored helmets are usually believed to increase rider conspicuity and thus lower risk of injury. However, note that a white outfit (such as a white helmet) may increase conspicuity in a more complex and multi colored urban environment, whereas, it can, in fact, decrease rider’s conspicuity where a background is solely a bright sky (such as on inter urban roads) (Gershonetal., 2012 ).”

Modern helmets are constructed from plastics. Premium price helmets are made with fiberglass reinforced with Kevlar or carbon fiber. They generally have fabric and foam interiors for both comfort and protection. Motorcycle helmets are generally designed to distort in a crash (thus expending the energy otherwise destined for the wearer's skull), so they provide little protection at the site of their first impact, but continued protection over the remainder of the helmet. Helmets are made with an inner EPS (expanded polystyrene foam) shell and an outer shell to protect the EPS. The density and the thickness of the EPS is designed to cushion or crush on impact to help prevent head injuries. Some manufacturers even offer different densities to offer better protection. The outer shell can be made of plastics or fiber materials. Some of the plastics offer very good protection from penetration as in Lexan (bullet resistant glass) but will not crush on impact, so the outer shell will look undamaged but the inner EPS will be crushed. Fiberglass is less expensive than Lexan but is heavy and very labor intensive. Fiberglass or fiber shells will crush on impact offering better protection. Some manufacturers will use Kevlar or carbon fiber to help reduce the amount of fiberglass but in the process it will make the helmet lighter and offer more protection from penetration but still crushing on impact. However, using these materials can be very expensive, and manufacturers will balance factors such as protection, comfort, weight, and additional features to meet target price points.

Motorcycle helmets greatly reduce injuries and fatalities in motorcycle accidents, thus many countries have laws requiring acceptable helmets to be worn by motorcycle riders. These laws vary considerably, often exempting mopeds and other small displacement bikes. In some countries, most notably the United States and India, there is opposition to compulsory helmet use (see Helmet Law Defense League); not all U. S. states have a compulsory helmet law. Many countries have set standards for the effectiveness of a motorcycle helmet, including the following.

One South American standard is NBR 7471 (Norma Brasileira by Associação Brasileira de Normas Técnicas, Brazil).

Most motorcycle helmet standards use impacts at speeds between 4–7 m/s (9–16 mph). While motorcyclists frequently ride at speeds higher than 20 m/s (45 mph), the perpendicular impact speed of the helmet is usually not the same as the road speed of the motorcycle, and the severity of the impact is determined not only by the speed of the head but also by the surface it hits and the angle of impact. Since the surface of the road is almost parallel to the direction a motorcyclist moves while driving, only a small component of their velocity is directed perpendicularly (though other surfaces may be perpendicular to the motorcyclist's velocity, such as trees, walls, and the sides of other vehicles). The severity of an impact is also influenced by the nature of the surface struck. The sheet metal wall of a car door may bend inwards to a depth of during a helmeted head impact, allowing more stopping distance for the rider's head than the helmet itself. A perpendicular impact against a flat steel anvil at 5 m/s (11 mph) may be of approximate severity to an oblique impact against a concrete surface at 30 m/s (67 mph) or a perpendicular impact against a sheet metal car door or windscreen at 30 m/s. Since there is a wide range of severity in the impacts that could happen in a motorcycle accident, some will be more severe than the impacts used in the standard tests and some will be less.