A blind spot in a vehicle or vehicle blind spot is an area around the vehicle that cannot be directly seen by the driver while at the controls, under existing circumstances. In

transport Transport (in British English) or transportation (in American English) is the intentional Motion, movement of humans, animals, and cargo, goods from one location to another. Mode of transport, Modes of transport include aviation, air, land tr ...

, driver visibility is the maximum distance at which the driver of a

vehicle A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velo ...

can see and identify prominent objects around the vehicle. Visibility is primarily determined by

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...

conditions (see

visibility In meteorology, visibility is the measure of the distance at which an object or light can be clearly discerned. It depends on the Transparency and translucency, transparency of the surrounding air and as such, it is unchanging no matter the amb ...

) and by a vehicle's design. The parts of a vehicle that influence visibility include the

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 ...

, the

dashboard A dashboard (also called dash, instrument panel or IP, or fascia) is a control panel (engineering), control panel set within the central console of a vehicle, boat, or cockpit of an aircraft or spacecraft. Usually located directly ahead of the ...

and the pillars. Good driver visibility is essential to safe road traffic. Warning Sign - Blind Spot

Conditions for blind spots

Blind spots exist in a wide range of vehicles: aircraft, cars, buses, trucks, agricultural equipment, heavy equipment, boats, ships, trams and trains. Blind spots may occur in the front of the driver when the A-pillar (also called the windshield pillar),

side-view mirror A side-view mirror (or side mirror), also known as a door mirror and often (in the UK) called a wing mirror, is a mirror placed on the exterior of motor vehicles for the purposes of helping the driver see areas behind and to the sides of the ...

, or interior

rear-view mirror A rear-view mirror (or rearview mirror) is a, usually plane mirror, flat, mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's rear window (rear windshield). In cars, the rear-view mirror ...

block a driver's view of the road. Behind the driver, cargo, headrests, and additional pillars may reduce visibility. Proper adjusting of mirrors and using other technical solutions can eliminate or alleviate vehicle blind spots. A no zone is one of several areas around a large truck, where the truck driver cannot see. Collisions frequently occur in no zones. A blind zone is one of several areas around heavier rolling stocks (locomotives and multiple units), where the train driver cannot see. Accidents frequently occur in blind zones.

Adjusting mirrors to reduce side blind spots

The side view mirrors of a car should be adjusted to reduce blind spots on the sides., which includes good illustrations of vision zones involved in proper adjustment. The method is frequently overlooked in

driver's education Driver's education, also known as driver's ed, driving education, driver training, or driving lessons, is a formal class or program that prepares a new driver to obtain a learner's permit or driver's license. The formal class program may also p ...

classes and takes some getting used to. Calculated elimination of blind spots by properly trained drivers is inexpensive and obviates the need for costly technological solutions to that problem, provided drivers take the time to set up and use their mirrors effectively. The arrangementpointing the side-view mirrors substantially outboard in a fixed mechanical formulais relatively simple to achieve. Still, it takes some knowledgeable effort and getting used to it. It is reputed to be a lifesaver. However, one source considers that method a driving mistake and claims it is even more dangerous than not using it, because it creates other blind spots directly behind the vehiclenine reasons are listed, ''e.g.'', when backing upwhich are impossible to eliminate by a "shoulder check". Rearward invisibility is an entirely different matter. The area directly behind vehicles is the source of backup collisions, particularly involving pedestrians, children, and objects directly aft of a vehicle. That area has been called a "killing zone". These problems are the object of several technological solutions, including (in rough order of technological complexity, simplest first):

Fresnel lens A Fresnel lens ( ; ; or ) is a type of composite compact lens (optics), lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections. The simpler Dioptrics, d ...

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

, parking sensors, and backup camera. A similar problem attaches to positions left and right of a vehicle's rear bumper as the driver attempts to back out of a parking space. Specially designed cross-traffic alert warning systems have been developed to address these.

Motor vehicles

As one is

driving Driving is the controlled operation and movement of a land vehicle, including cars, motorcycles, trucks, and buses. A driver's permission to drive on public highways is granted based on a set of conditions being met, and drivers are required to ...

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 ...

, blind spots are the areas of the

road A road is a thoroughfare used primarily for movement of traffic. Roads differ from streets, whose primary use is local access. They also differ from stroads, which combine the features of streets and roads. Most modern roads are paved. Th ...

that cannot be seen while looking forward or through either the rear-view or side mirrors (expecting that the side mirrors are properly adjusted on a passenger auto see above). The most common are the ''rear quarter blind spots,'' areas towards the rear of the vehicle on both sides. Vehicles in the adjacent lanes of the road that fall into these blind spots may not be visible using only the car's mirrors. Rear quarter blind spots can be: * checked by turning one's head briefly (risking rear-end collisions), * reduced by installing mirrors with larger fields-of-view, or * eliminated by reducing overlap between side and rear-view mirrors by adjusting side mirrors so the side of the car is barely visible when your head is between the front seats (for the passenger-side mirror) and almost touching the driver's window (for the driver-side mirror), then checking to be sure you can see cars approaching from behind on either side when on the highway. Other areas that are sometimes called blind spots are those that are too low to see behind, in front, or to the sides of a vehicle, especially those with a high seating point.

Forward visibility

This diagram shows the blocked view in a horizontal plane in front of the driver. The front-end blind spots caused by this can create problems in

traffic Traffic is the movement of vehicles and pedestrians along land routes. Traffic laws govern and regulate traffic, while rules of the road include traffic laws and informal rules that may have developed over time to facilitate the orderly an ...

situations, such as in

roundabouts A roundabout, a rotary and a traffic circle are types of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junct ...

, intersections, and road crossings. Front-end blind spots are influenced by the following design criteria: *Distance between the driver and the pillar *Thickness of the pillar *The angle of the pillar in a vertical plane side view *The angle of the pillar in a vertical plane front view *the form of the pillar is straight or arc-form *Angle of the windshield *Height of the driver about the dashboard *Speed of the opposite car The front left side A-pillar (not shown in the illustration) also causes blind spot issues when a car approaches a pedestrian crossing while a pedestrian is crossing the street left to right.

Types of A-pillar design

Most passenger cars have a diagonal pillar in the side view. The angle between the horizon and A-pillar is approximately 40 degrees with a straight pillar that is not too thick. This gives the car a strong, aerodynamic body with an adequately sized front door.

Panoramic vertical A-pillars

The sides of a panoramic

are curved, which makes it possible to design vertical A-pillars that give the driver maximum forward visibility. However, it is impossible to design an aerodynamic small car with a vertical A-pillar because the more vertical the A-pillar is, the less space the door opening has, and the greater frontal area and coefficient of drag the vehicle will have. Examples of cars with an almost vertical A-pillar: *

Honda commonly known as just Honda, is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate automotive manufacturer headquartered in Minato, Tokyo, Japan. Founded in October 1946 by Soichiro Honda, Honda has bee ...

Step Bus Concept * Saab 900 *

School bus A school bus is any type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to Student transport, transport students to and from school or school-related activities, but not including a charter ...

*Almost all

Cadillac Cadillac Motor Car Division, or simply Cadillac (), is the luxury vehicle division (business), division of the American automobile manufacturer General Motors (GM). Its major markets are the United States, Canada and China; Cadillac models are ...

s from 1954 to 1959

Flat A-pillar design

Some modern car designs have an extremely flat A-pillar angle with the horizon. For example, the

Pontiac Firebird The Pontiac Firebird is an American automobile built and produced by Pontiac (automobile), Pontiac from the 1967 to 2002 model years. Designed as a pony car to compete with the Ford Mustang, it was introduced on February 23, 1967, five months a ...

and

Chevrolet Camaro The Chevrolet Camaro is a mid-size American automobile manufactured by Chevrolet, classified as a pony car. It first went on sale on September 29, 1966, for the 1967 model year and was designed to compete with the Ford Mustang. The Camaro sha ...

from 1993 to 2002 had a windshield angle of 68° with the vertical, which equals just 22° with the horizon. A flatter A-pillar's advantages include reducing the overall drag coefficient and making the car body stronger in a frontal collision, at the expense of reducing driver visibility in a 180° field of view from left to right. A flatter A-pillar (and therefore windscreen) is also a factor when calculating the effects of a collision with a pedestrian. In general, a flatter angle will result in a more gentle impact, directing the pedestrian "up and over" rather than directly into the windscreen. This is particularly true for cars like the Mercedes-Benz A-Class which also have a low angled engine cover.

=Other disadvantages of a flat windshield angle

= *Other traffic can not see the driver through the reflection if the driver can see them. *The heater needs more time to heat the bigger window surface. *The flat windshield angle does not let the snow slide off easily. *The driver cannot reach the whole flat window to clean it easily.

Height of the driver

Driver height can also affect visibility. An A-pillar that is split up and has a small triangle window (Front Quarter glass) can give short driver visibility problems. In some cars, the windshield is fillet with the roof-line with a big radius. A fillet round A-pillar can give a tall driver visibility problems. Also sometimes the A-pillar can block the driver from seeing motorcyclists. Also, the

B-pillar The pillars on a car with permanent roof body style (such as four-door sedans) are the vertical or nearly vertical supports of its window area or greenhouse—designated respectively as the A, B, C and (in larger cars such as 4-door stati ...

can block the vision of a tall driver in small 4-door cars. A driver may reduce the size of a blind spot or eliminate it by turning their head in the direction of the obstruction. This allows the driver to see better around the obstruction and allows the driver better depth perception.

Visibility in a convertible

Because there is no roof connection between the A- and B-pillars, the A-pillars of a

convertible A convertible or cabriolet () is a Car, passenger car that can be driven with or without a roof in place. The methods of retracting and storing the roof vary across eras and manufacturers. A convertible car's design allows an open-air drivin ...

automobile have to be stronger and even thicker. However, with the top down there are no B or C pillars, improving visibility behind the driver.

Windshield reflections

Dashboard reflection

It is best if the dashboard has a non-reflecting dark-colored surface.NX General Packaging Intelligent Tools for Automotive Mechanical and Occupancy Packaging
A small dashboard gives some reflection on the lower part of the windshield. A big dashboard can give a reflection on eye height.

A-pillar reflection

It is best if the inside of the A-pillar has a non-reflecting dark-colored surface. If the side of the window is curved there is less A-pillar reflection.

Light through roof reflection

Some new model cars have a very big

sunroof A sunroof is a movable panel that opens to uncover a window in an automobile roof, allowing light and fresh air to enter the passenger compartment. Sunroofs can be manually operated or motor driven, and are available in many shapes, sizes and s ...

. Sometimes the

sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

through the roof lights up the dashboard and gives a reflection in the windshield.

Other automobile design factors

Other design factors may prevent a manufacturer from maximizing visibility. These include safety, as narrower pillars cannot be made strong as easily as thicker pillars, and size restraints about aerodynamics, as taller, more vertical windshields create additional drag and reduce fuel efficiency. They also include fashion and cost, whereby design and appearance considerations can be deemed preeminent. Side radar systems offer better performance and also warn of fast-approaching vehicles entering the blind spot.

Trams and trains

Blind spots also exist around trams (streetcars/trolleys) and trains (locomotives with railway carriages and multiple units). Heavier rolling stocks can have up to several meters of blind spot. This is generally known as the dead visual range of a train. To address this, cameras are sometimes placed around the train driver's cab to cover the missing field of view during coupling/decoupling between locomotives and railcars, multiple units, special railway equipments or another locomotives.

Agricultural equipment

Blind spots also exist around agricultural equipment (utility tractors, combine harvesters, etc.).

Heavy equipment

Blind spots also exist around heavy equipment (excavators, bulldozers, wheel loaders, cranes, etc.).

Boats and ships

Blind spots also exist in front of boats and ships. When the boat accelerates, the bow rises, increasing the size of the blind spot. Large vessels can have up to several hundreds of meters of blind spots. This is generally known as the dead visual range of a ship. To address this, cameras are sometimes placed in the front of the vessel to cover the missing field of view. Blind spots exist where areas behind the sail are obscured from the view of a

helmsman A helmsman or helm (sometimes driver or steersman) is a person who steering, steers a ship, sailboat, submarine, other type of maritime vessel, airship, or spacecraft. The rank and seniority of the helmsman may vary: on small vessels such as fis ...

on a

sailboat A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture. Types Although sailboat terminology ...

windsurfer Windsurfing is a wind-propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the Californian aerospace and surf culture. Windsurfing gain ...

. This is especially true when they are heeled over; consequently, transparent windows are sometimes sewn into the sails.

Aircraft

Blind spots also exist around aircraft (helicopters, airships, airplanes, gliders). When the aircraft (airplane) accelerates for take off, the size of the blind spot below fuselage increases. Heavier aircraft can have up to several meters of blind spots. This is generally known as the dead visual range of an aircraft. To address this, cameras are sometimes placed in the front of the aircraft to cover the missing field of view.

References

External links

* * *{{cite web , url= https://www.cdc.gov/niosh/topics/highwayworkzones/BAD/imagelookup.html , work=Highway Work Zone Safety , title=Construction Equipment Blind Areas , publisher=National Institute for Occupational Safety and Health , access-date=August 9, 2013 Automotive safety Railway safety