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 movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelin ...

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

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...

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 cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the ...

conditions (see

visibility The visibility is the measure of the distance at which an object or light can be clearly discerned. In meteorology it depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time o ...

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

windshield The windshield (North American 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 the elements. ...

, the

dashboard For business applications, see Dashboard (business). A dashboard (also called dash, instrument panel (IP), or fascia) is a control panel set within the central console of a vehicle or small aircraft. Usually located directly ahead of the drive ...

and the

pillars A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

. 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 equipments, heavy equipments, boats, ships, trams, and trains. Blind spots may occur in the front of the driver when the

A-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 ...

(also called the windshield pillar),

side-view mirror A side-view mirror (or side mirror), also known as 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 vehicle, outside the driver's peripheral v ...

, or interior

rear-view mirror A rear-view mirror (or rearview mirror) is a 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 is usually affixed to ...

block a driver's view of the road. Behind the driver, cargo, headrests, and additional

may reduce visibility. Proper adjustment of mirrors and the use of 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, driver education, driving education, driver's ed, driving tuition 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 als ...

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, but it takes some knowledgeable effort and getting used to. It is reputed to be a lifesaver., which includes good illustrations of vision zones involved in proper adjustment. 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

back-up collision Back-up collisions happen when a driver reverses the car into an object, person, or other car. Although most cars come equipped with rear view mirrors which are adequate for detecting vehicles behind a car, they are inadequate on many vehicles for ...

s, 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 a number of technological solutions, including (in rough order of technological complexity, simplest first):

fresnel lens A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the c ...

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 on o ...

parking sensors Parking sensors are proximity sensors for road vehicles designed to alert the driver of obstacles while parking. These systems use either electromagnetic or ultrasonic sensors. Ultrasonic systems These systems feature ultrasonic proximity de ...

, and

backup camera A backup camera (also called a reversing camera or rear-view camera) is a special type of video camera that is produced specifically for the purpose of being attached to the rear of a vehicle to aid in backing up and to alleviate the rear blind s ...

. A similar problem attaches to positions left and right of a vehicles' 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 vehicle, including cars, motorcycles, trucks, buses, and bicycles. 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 automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

, blind spots are the areas of the

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types o ...

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 comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffic ...

situations, such as in

roundabouts A roundabout is a type 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 junction.''The New Shorter Oxford Eng ...

intersections In mathematics, the intersection of two or more objects is another object consisting of everything that is contained in all of the objects simultaneously. For example, in Euclidean geometry, when two lines in a plane are not parallel, their ...

, 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 straight or arc-form *Angle of the windshield *Height of the driver in relation to the dashboard *Speed of the opposite car

Types of A-pillar design

Most passenger cars have a diagonal pillar in the side view. The angle between the horizon and

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 is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a producti ...

Step Bus Concept *

Saab 900 The Saab 900 is a mid-sized automobile which was produced by Saab from 1978 until 1998 in two generations; the first from 1978 to 1993, and the second from 1994 to 1998. The first-generation car was based on the Saab 99 chassis, though with a ...

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 transport students to and from school or school-related activities, but not including a charter bus or transit bus ...

*Almost all

Cadillac The Cadillac Motor Car Division () is a division of the American automobile manufacturer General Motors (GM) that designs and builds luxury vehicles. Its major markets are the United States, Canada, and China. Cadillac models are distributed ...

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 that was built and produced by 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 after GM's ...

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 ...

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 In fluid dynamics, the drag coefficient (commonly denoted as: c_\mathrm, c_x or c_) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag e ...

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 The Mercedes-Benz A-Class is a subcompact car produced by the German automobile manufacturer Mercedes-Benz as the brand's entry-level vehicle. The first generation (internally coded W168) was introduced in 1997, the second generation (W169) i ...

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 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 Quarter glass (or quarter light) on automobiles and closed carriages may be a side window in the front door or located on each side of the car just forward of the rear-facing rear window of the vehicle. Only some cars have them. In some cases, ...

) can give a short driver visibility problems. 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 Sedan (automobile), sedans) are the vertical or nearly vertical supports of its window area or Greenhouse (automotive), greenhouse—designated respectively as the ''A, B, ...

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 completely 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 passenger car that can be driven with or without a roof in place. The methods of retracting and storing the roof vary among eras and manufacturers. A convertible car's design allows an open-air driving expe ...

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 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 styl ...

. Sometimes the

sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when ...

through the roof lights up the dashboard and gives a

reflection Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, reflection from a smooth surface *** Mirror image, a reflection in a mirror or in water ** Signal reflection, in ...

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 pertaining to 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 freight cars (goods wagons) and/or passenger cars (carriages/coaches) 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 train driver's cab to cover the missing field of view.

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 spot. 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) is a person who steers a ship, sailboat, submarine, other type of maritime vessel, or spacecraft. The rank and seniority of the helmsman may vary: on small vessels such as fishing vessels and yachts, t ...

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 aerospace and surf culture of California. Windsurfing ga ...

. 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, increasing the size of the blind spot below fuselage. Heavier aircraft can have up to several meters of blind spot. 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