A rear-view mirror (or rearview mirror) is a, usually flat, mirror in

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

s and other vehicles, designed to allow the driver to see rearward through the vehicle's rear window (rear

windshield The windshield (American English and Canadian English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike, truck, train, boat or streetcar is the front window, which provides visibility while protecting occupants from t ...

). In cars, the rear-view mirror is usually affixed to the top of the

on a double-

swivel A swivel is a connection that allows the connected object, such as a swivel gun, gun, swivel chair, chair, Caster, swivel caster, or an anchor rode to rotate horizontally or vertically. Swivel designs A common design for a swivel is a cylindr ...

mount allowing it to be adjusted to suit the height and viewing angle of any driver and to swing harmlessly out of the way if impacted by a vehicle occupant in a

collision In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great for ...

. The rear-view mirror is augmented by one or more side-view mirrors, which serve as the only rear-vision mirrors on

trucks A truck or lorry is a motor vehicle designed to transport freight, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

motorcycle A motorcycle (motorbike, bike; uni (if one-wheeled); trike (if three-wheeled); quad (if four-wheeled)) is a lightweight private 1-to-2 passenger personal motor vehicle Steering, steered by a Motorcycle handlebar, handlebar from a saddle-style ...

s and

bicycle A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered transport, human-powered or motorized bicycle, motor-assisted, bicycle pedal, pedal-driven, single-track vehicle, with two bicycle wheel, wheels attached to a ...

History

Early use of fixed mirrors was described as early as 1906, with a trade magazine noting mirrors for showing what is coming behind were now popular on closed bodied automobiles, and were likely to be widely adopted in a short time. The same year, a Mr. Bilal Ghanty from

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

patented a "''Warning mirror for automobiles''". The Argus Dash Mirror, adjustable to any position to see the road behind, appeared in 1908. Earliest known rear-view mirror mounted on a racing vehicle appeared on Ray Harroun's Marmon race car at the inaugural

Indianapolis 500 The Indianapolis 500, formally known as the Indianapolis 500-Mile Race, and commonly shortened to Indy 500, is an annual automobile race held at the Indianapolis Motor Speedway in Speedway, Indiana, United States, an enclave suburb of Indian ...

race in 1911. Harroun himself claimed he got the idea from seeing a mirror used for a similar purpose on a

horse-drawn vehicle A horse-drawn vehicle is a piece of equipment pulled by one or more horses. These vehicles typically have two or four wheels and were used to carry passengers or a load. They were once common worldwide, but they have mostly been replaced by auto ...

in 1904. Harroun also claimed that the mirror vibrated constantly due to the rough brick surface, and it was rendered largely useless. Elmer Berger is usually credited with inventing the rear-view mirror, though in fact he was the first to patent it (1921) and develop it for incorporation into production street going automobiles by his Berger and Company.

Augmentations and alternatives

Recently, rear-view video cameras have been built into many new model cars, this was partially in response to the rear-view mirrors' inability to show the road directly behind the car, due to the rear deck or trunk obscuring as much as 3–5 meters (10–15 feet) of road behind the car. As many as 50 small children are killed by SUVs every year in the USA because the driver cannot see them in their rear-view mirrors. Camera systems are usually mounted to the rear bumper or lower parts of the car, allowing for better rear visibility. Aftermarket secondary rear-view mirrors are available. They attach to the main rear-view mirror and are independently adjustable to view the back seat. This is useful to enable adults to monitor children in the back seat.

Anti-glare

prismatic An optical prism is a transparent optics, optical element with flat, polished surfaces that are designed to refraction, refract light. At least one surface must be angled—elements with two parallel surfaces are ''not'' prisms. The most fami ...

rear-view

mirror A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...

—sometimes called a "day/night mirror"—can be tilted to reduce the brightness and

glare Glare may refer to: * Glare (vision), difficulty seeing in the presence of very bright light * Glaring, a facial expression of squinted eyes and look of contempt * A call collision in telecommunications * GLARE, Glass reinforced aluminium, an ...

of lights, mostly for high-beam

headlight A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for t ...

s of vehicles behind which would otherwise be reflected directly into the driver's eyes at night. This type of mirror is made of a piece of glass that is wedge-shaped in cross-section—its front and rear surfaces are not parallel. On manual tilt versions, a tab is used to adjust the mirror between "day" and "night" positions. In the day view position, the front surface is tilted and the reflective back side gives a strong reflection. When the mirror is moved to the night view position, its reflecting rear surface is tilted out of line with the driver's view. This view is actually a reflection of the low-reflection front surface; only a much-reduced amount of light is reflected in the driver's eyes. "Manual tilt" day/night mirrors first began appearing in the 1930s and became standard equipment on most passenger cars and trucks by the early 1970s.

Automatic dimming

In the 1940s, American inventor

Jacob Rabinow Jacob Rabinow (January 8, 1910 – September 11, 1999) was an American engineer and inventor. He earned a total of 229 U.S. patents on a variety of mechanical, optical and electrical devices. Biography Rabinow was born in Kharkiv, Ukraine, on Ja ...

developed a light-sensitive automatic mechanism for the wedge-type day/night mirror. Several

Chrysler Corporation FCA US, LLC, doing business as Stellantis North America and known historically as Chrysler ( ), is one of the " Big Three" automobile manufacturers in the United States, headquartered in Auburn Hills, Michigan. It is the American subsidiary of ...

cars offered these automatic mirrors as optional equipment as early as 1959, but few customers ordered them for their cars and the item was soon withdrawn from the option lists. Several automakers began offering rear-view mirrors with automatic dimming again in 1983, and it was in the late 1980s that they began to catch on in popularity. Current systems usually use

photosensor Photodetectors, also called photosensors, are devices that detect light or other forms of electromagnetic radiation and convert it into an electrical signal. They are essential in a wide range of applications, from digital imaging and optical c ...

s mounted in the rear-view mirror to detect light and dim the mirror by means of electrochromism. This electrochromic feature has also been incorporated into side-view mirrors allowing them to dim and reduce glare as well.

Suspending objects

Objects are sometimes hung from the rear-view mirror, including

cross necklace __NOTOC__ A cross necklace is any necklace featuring a Christian cross or crucifix as its pendant. Crosses are often worn as an indication of commitment to the Christian faith, and are sometimes received as gifts for rites such as baptism and c ...

s, prayer beads,

good luck charm "Good Luck Charm" is a song recorded by Elvis Presley and published by Gladys Music, Elvis Presley's publishing company, that reached number 1 on the ''Billboard'' Hot 100 list in the week ending April 21, 1962. It remained at the top of the lis ...

s, decorations like fuzzy dice, and air fresheners like Little Trees. In some jurisdictions such hanging is illegal on the basis that it impairs the driver's forward view and so compromises safety.

Black Lives Matter Black Lives Matter (BLM) is a Decentralization, decentralized political and social movement that aims to highlight racism, discrimination and Racial inequality in the United States, racial inequality experienced by black people, and to pro ...

protesters have cited this as an example of the minor violations used as grounds for

traffic stop A traffic stop, colloquially referred to as being pulled over, is a temporary Detention (imprisonment), detention of a driver of a vehicle and its occupants by police to Criminal investigation, investigate a possible crime or minor violation o ...

s disproportionately targeting black drivers.

Trucks and buses

On trucks and buses, the load often blocks rearward vision out the backlight. In the U.S. virtually all trucks and buses have a side view mirror on each side, often mounted on the doors and viewed out the side windows, which are used for rear vision. These mirrors leave a large unviewable ("blind") area behind the vehicle, which tapers down as the distance increases. This is a safety issue which the driver must compensate for, often with a person guiding the truck back in congested areas, or by backing in a curve. "Spot mirrors", a

convex mirror A curved mirror is a mirror with a curved reflecting surface. The surface may be either ''convex'' (bulging outward) or ''concave'' (recessed inward). Most curved mirrors have surfaces that are shaped like part of a sphere, but other shapes are ...

which provides a distorted image of the entire side of the vehicle, are commonly mounted on at least the right side of a vehicle. In the U.S. mirrors are considered "safety equipment", and are not included in width restrictions.

Motorcycles

Depending on the type of motorcycle, the motorcycle may or may not have rear-view mirrors. Street-legal motorcycles are generally required to have rear-view mirrors. Motorcycles for off-road use only normally do not have rear-view mirrors. Rear-view mirrors come in various shapes and designs and have various methods of mounting the mirrors to the motorcycle, most commonly to the handlebars. Rear-view mirrors can also be attached to the rider's

motorcycle helmet 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 4 ...

. The Reevu MSX1 helmet uses an internal periscope that allows the user rear vision.

Bicycles

Some

s are equipped with a rear-view mirror mounted on a handlebar. Rear-view mirrors may also be fitted to the

bicycle frame A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangle ...

, on a

helmet A helmet is a form of protective gear worn to protect the head. More specifically, a helmet complements the skull in protecting the human brain. Ceremonial or symbolic helmets (e.g., a policeman's helmet in the United Kingdom) without protecti ...

, on the

arm In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between ...

or the frame of a pair of

eyeglasses Glasses, also known as eyeglasses (American English), spectacles (Commonwealth English), or colloquially as specs, are Visual perception, vision eyewear with clear or tinted lens (optics), lenses mounted in a frame that holds them in front ...

. This allows what is behind to be checked continuously without turning round. Rear-view mirrors almost never come with a new bicycle and require an additional purchase.

Aircraft

By 1956, the Civil Aeronautics Administration had approved a rear-view mirror for light aircraft."Periscopes for Aircraft"
''Popular Mechanics'', June 1956, p. 142. They also predicted periscopes in larger aircraft. Fighter aircraft usually have one or more rear-view mirrors mounted on the front canopy frame to watch out for chasing aircraft.

References

{{DEFAULTSORT:Rear View Mirror 1911 introductions Mirrors Vehicle parts