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Automobile safety system evolution: Automobile safety is the study and practice of design cars, construction, equipment and regulation to minimize the occurrence and consequences of traffic collisions. Road traffic safety more broadly includes roadway design. One of the first formal academic studies into improving vehicle safety was by Cornell Aeronautical Laboratory of Buffalo, New York. The main conclusion of their extensive report is the crucial importance of seat belts and padded dashboards. However, the primary vector of traffic-related deaths and injuries is the disproportionate mass and velocity of an automobile compared to that of the predominant victim, the pedestrian. In the United States a pedestrian is injured by an automobile every 8 minutes, and are 1.5 times more likely than a vehicle's occupants to be killed in an automobile crash per outing. Improvements in roadway and automobile designs have steadily reduced injury and death rates in all first world countries. Nevertheless, auto collisions are the leading cause of injury- related deaths, an estimated total of 1.2 million in 2004, or 25% of the total from all causes. Of those killed by autos, nearly two-thirds are pedestrians. Risk compensation theory has been used in arguments against safety devices, regulations and modifications of vehicles despite the efficacy of saving lives. The terms "active" and "passive" are simple but important terms in the world of automotive safety. " Active safety " is used to refer to technology assisting in the prevention of a crash and

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Page 1: Automobile

Automobile safety system evolution: Automobile safety is the study and practice of design

cars, construction, equipment and regulation to minimize the occurrence and consequences

of traffic collisions. Road traffic safety more broadly includes roadway design. One of the first

formal academic studies into improving vehicle safety was by Cornell Aeronautical

Laboratory of Buffalo, New York. The main conclusion of their extensive report is the crucial

importance of seat belts and padded dashboards. However, the primary vector of traffic-related

deaths and injuries is the disproportionate mass and velocity of an automobile compared to that

of the predominant victim, the pedestrian. In the United States a pedestrian is injured by an

automobile every 8 minutes, and are 1.5 times more likely than a vehicle's occupants to be killed

in an automobile crash per outing.

Improvements in roadway and automobile designs have steadily reduced injury and death rates

in all first world countries. Nevertheless, auto collisions are the leading cause of injury-related

deaths, an estimated total of 1.2 million in 2004, or 25% of the total from all causes. Of those

killed by autos, nearly two-thirds are pedestrians. Risk compensation theory has been used in

arguments against safety devices, regulations and modifications of vehicles despite the efficacy

of saving lives.

The terms "active" and "passive" are simple but important terms in the world of automotive

safety. "Active safety" is used to refer to technology assisting in the prevention of a crash and

"passive safety" to components of the vehicle (primarily airbags, seatbelts and the physical

structure of the vehicle) that help to protect occupants during a crash.

Crash avoidance:

Crash avoidance systems and devices help the driver and, increasingly, help the vehicle itself to

avoid a collision. This category includes:

1. The vehicle's headlamps, reflectors, and other lights and signals

2. The vehicle's mirrors

3. The vehicle's brakes, steering, and suspension systems

The term active safety (or primary safety) is used in two distinct ways.

Page 2: Automobile

The first, mainly in the United States, refers to safety systems that help avoid accidents, such as

good steering and brakes. In this context, passive safety refers to features that help reduce the

effects of an accident, such as seat belts, airbags and strong body structures. This use is

essentially interchangeable with the terms primary and secondary safety that tend to be used in

the UK.

However, active safety is increasingly being used to describe systems that use an understanding

of the state of the vehicle to both avoid and minimise the effects of a crash. These include

braking systems, like brake assist, traction control systems and electronic stability control

systems, that interpret signals from various sensors to help the driver control the vehicle.

Additionally, forward-looking, sensor-based systems such as Advanced Driver Assistance

Systems including adaptive cruise control and collision warning/avoidance/mitigation systems

are also considered as active safety systems under this definition.

These forward-looking technologies are expected to play an increasing role in collision

avoidance and mitigation in the future. Most major component suppliers, such as Delphi, TRW

and Bosch, are developing such systems. However, as they become more sophisticated, questions

will need to be addressed regarding driver autonomy and at what point these systems should

intervene if they believe a crash is likely.

In engineering, active safety systems are systems activated in response to a safety problem or

abnormal event. Such systems may be activated by a human operator, automatically by

a computer driven system, or even mechanically. In nuclear engineering, active safety contrasts

to passive safety in that it relies on operator or computer automated intervention, whereas

passive safety systems rely on the laws of nature to make the reactor respond to dangerous events

in a favourable manner.

A collision avoidance system is an automobile safety system designed to reduce the severity of

an accident. Also known as precrash system, forward collision warning system or collision

mitigating system, it uses radar (all-weather) and sometimes laser and camera (both sensor types

are ineffective during bad weather) to detect an imminent crash. Once the detection is done,

these systems either provide a warning to the driver when there is an imminent collision or take

action autonomously without any driver input (by braking or steering or both). Collision

avoidance by braking is appropriate at low vehicle speeds (e.g. below 50 km/h), while collision

Page 3: Automobile

avoidance by steering is appropriate at higher vehicle speeds.[1] Cars with collision avoidance

may also be equipped with adaptive cruise control, and use the same forward-looking sensors.

Driver assistance:

A subset of crash avoidance is driver assistance systems, which help the driver to detect

obstacles and to control the vehicle. Driver assistance systems include

1. Automatic Braking systems to prevent or reduce the severity of collision: Automatic

braking is a technology for automobiles to sense an imminent collision with another

vehicle, person or obstacle; or a danger such as a high brakes or by applying the brakes to

slow the vehicle without any driver input. Sensors to detect other vehicles or obstacles

can include radar, video, infrared, ultrasonic or other technologies. GPS sensors can

detect fixed dangers such as approaching the stop signs through a location database. 

Automatic braking by the system after sensing an obstacle can be executed in two modes. In

collision avoidance,the collision is avoided by the automatic braking, but the driver will not be

warned in this type of system. There is a very good chance of wrongly interpreting the signals,

especially in the case of radars or lasers. So this is not so effective method of automatic braking.

In collision mitigation system,the sensors detect the possibility of collision but will not take

immediate action. A warning will be sent to the driver in the form of a signal or a voice message.

There is a threshold safe distance calculated by the system and if the driver fails to respond even

when the vehicle crosses that region, then only brakes will be applied automatically. Even if

there is a mis-interpretation of signals, there is no problem because, the decision to apply brakes

is left with the driver and the brakes are applied automatically only in the most emergency

situations. Many vehicles are provided with the option of turning on or off the automatic system

based on their surroundings. In some automobiles even though they cannot be completely

disabled, they can be limited to warning the driver about coming obstacle. Even this emergency

braking initiates ABS which help the driver to retain the control over vehicle without any

skidding. Automatic braking system is only effective if the mode of sensing the obstacles is

reliable, or else any kind of false interpretation may cause a lot of damage.

2. Infrared night vision systems to increase seeing distance beyond headlamp range:

An automotive night vision system uses a thermographic camera to increase

Page 4: Automobile

a driver's perception and seeing distance in darkness or poor weather beyond the reach of

the vehicle's headlights. Such systems are offered as optional equipment on certain

premium vehicles. The first introduction was in 2000 on Cadillac Deville.[1]

Active systems use an infrared light source built into the car to illuminate the road ahead with

light that is invisible to humans. There are two kinds of active systems: gated and non-gated. The

gated system uses a pulsed light source and a synchronized camera that enable long ranges

(250m) and high performance in rain and snow.

Pros: higher resolution image, superior picture of inanimate objects, works better in warmer

conditions, smaller sensor can be mounted to rearview mirror.

Cons: does not work as well in fog or rain, lower contrast for animals, shorter range of 150–200

meters or 500–650 feet

3. Adaptive headlamps control the direction and range of the headlight beams to light the

driver's way through curves and maximize seeing distance without partially blinding

other drivers

4. Reverse backup sensors, which alert drivers to difficult-to-see objects in their path when

reversing: In the broadest definition, a sensor is an object whose purpose is to detect

events or changes in its environment, and then provide a corresponding output. A sensor

is a type of transducer; sensors may provide various types of output, but typically use

electrical or optical signals. For example, a thermocouple generates a known voltage (the

output) in response to its temperature (the environment). A mercury-in-glass

thermometer, similarly, converts measured temperature into expansion and contraction of

a liquid, which can be read on a calibrated glass tube.

The sensitivity may in practice differ from the value specified. This is called a sensitivity

error.

5. Backup camera: A backup camera (also called reversing 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 spot. Backup cameras are

alternatively known as 'reversing cameras' or 'rear view cameras'. It is specifically

Page 5: Automobile

designed to avoid a Backup collision. The area directly behind vehicles has been

described as a "killing zone" due to the associated carnage. Backup cameras are usually

connected to the vehicle head unit display.

6. Adaptive cruise control which maintains a safe distance from the vehicle in front:

Autonomous cruise control (ACC; also called adaptive cruise control or radar cruise

control) is an optional cruise control system for road vehicles that automatically adjusts

the vehicle speed to maintain a safe distance from vehicles ahead. It makes no use of

satellite or roadside infrastructures nor of any cooperative support from other vehicles.

Hence control is imposed based on sensor information from on-

board sensors only. Cooperative Adaptive Cruise Control (CACC) further extends the

automation of navigation by using information gathered from fixed infrastructure such as

satellites and roadside beacons, or mobile infrastructure such as reflectors or transmitters

on the back of other vehicles.

7. Lane departure warning systems to alert the driver of an unintended departure from the

intended lane of travel: In road-transport terminology, a lane departure warning

system is a mechanism designed to warn a driver when the vehicle begins to move out of

its lane (unless a turn signal is on in that direction) on freeways and arterial roads. These

systems are designed to minimize accidents by addressing the main causes of collisions:

driver error, distractions and drowsiness. In 2009 the U.S. National Highway Traffic

Safety Administration (NHTSA) began studying whether to mandate lane departure

warning systems and frontal collision warning systems on automobiles.

8. Tire pressure monitoring systems or Deflation Detection Systems:

9. A traction control system (TCS), in German known

as Antriebsschlupfregelung (ASR), is typically (but not necessarily) a secondary

function of the electronic stability control(ESC) on production motor vehicles, designed

to prevent loss of traction of driven road wheels. TCS is activated when throttle input and

engine torque are mismatched to road surface conditions.

Intervention consists of one or more of the following:

Brake force applied to one or more wheels

Reduction or suppression of spark sequence to one or more cylinders

Page 6: Automobile

Reduction of fuel supply to one or more cylinders

Closing the throttle, if the vehicle is fitted with drive by

wire throttleIn turbocharged vehicles, a boost control solenoid is actuated to reduce boost

and therefore engine power.

10. Electronic Stability Control, which intervenes to avert an impending loss of control:

Electronic stability control (ESC), also referred to as electronic stability

program (ESP) or dynamic stability control (DSC), is a computerized technology [1]

[2] that improves a vehicle's stability by detecting and reducing loss of traction (skidding).[3] When ESC detects loss of steering control, it automatically applies the brakes to help

"steer" the vehicle where the driver intends to go. Braking is automatically applied to

wheels individually, such as the outer front wheel to counter oversteer or the inner rear

wheel to counterundersteer. Some ESC systems also reduce engine power until control is

regained. ESC does not improve a vehicle's cornering performance; instead, it helps to

minimize the loss of control. According to Insurance Institute for Highway Safety and the

U.S. National Highway Traffic Safety Administration, one-third of fatal accidents could

be prevented by the use of the technology.[4][5]

11. Anti-lock braking systems: Anti-lock braking system (ABS) is an automobile

safety system that allows the wheels on a motor vehicle to maintain tractive contact with

the road surface according to driver inputs while braking, preventing the wheels from

locking up (ceasing rotation) and avoiding uncontrolled skidding. It is an automated

system that uses the principles of threshold braking and cadence braking which were

practiced by skillful drivers with previous generation braking systems. It does this at a

much faster rate and with better control than a driver could manage.

ABS generally offers improved vehicle control and decreases stopping distances on dry and

slippery surfaces; however, on loose gravel or snow-covered surfaces, ABS can significantly

increase braking distance, although still improving vehicle control.[1][2][3]

Since initial widespread use in production cars, anti-lock braking systems have been improved

considerably. Recent versions not only prevent wheel lock under braking, but also electronically

control the front-to-rear brake bias. This function, depending on its specific capabilities and

Page 7: Automobile

implementation, is known as electronic brakeforce distribution (EBD), traction control system,

emergency brake assist, or electronic stability control (ESC).

12. Electronic brakeforce distribution systems: Electronic brakeforce

distribution (EBD or EBFD) or electronic brakeforce limitation (EBL) is

an automobile brake technology that automatically varies the amount of forceapplied to

each of a vehicle's brakes, based on road conditions, speed, loading, etc. Always coupled

with anti-lock braking systems, EBD can apply more or less braking pressure to each

wheel in order to maximize stopping power whilst maintaining vehicular control. [1]

[2] Typically, the front end carries the most weight and EBD distributes less braking

pressure to the rear brakes so the rear brakes do not lock up and cause a skid. [3] In some

systems, EBD distributes more braking pressure at the rear brakes during initial brake

application before the effects of weight transfer become apparent.

Under heavy braking, vehicle wheels may lock-up due to excessiveness of wheel torques

over tire-road friction forces available, caused by too much hydraulic line pressure. Theanti-

lock braking system (ABS) monitors wheel speeds and releases pressure on individual wheel

brake lines, rapidly pulsing individual brakes to prevent lock-up. During heavy braking,

preventing wheel lock-up helps the driver maintain steering control. Modern ABS has an

individual brake line for each of the four wheels, enabling different braking pressure on

different road surfaces. For example, less braking pressure is needed to lock a wheel on ice

than a wheel which is on bare asphalt. If the left wheels are on asphalt and the right wheels

are on ice, during an emergency stop, ABS detects the right wheels about to lock and reduces

braking force on the right wheels, helping to avoid lock-up and loss of vehicle control.

13. Emergency brake assist systems: Emergency brake assist (EBA) or Brake Assist (BA

or BAS) is a generic term for an automobile braking technology that increases braking

pressure in an emergency. The first application was developed jointly by Daimler-

Benz and TRW/LucasVarity. Research conducted in 1992 at the Mercedes-Benz driving

simulator in Berlin revealed that more than 90% of drivers fail to brake with enough

force when faced with an emergency.

Page 8: Automobile

By interpreting the speed and force with which the brake pedal is pushed, the system detects if

the driver is trying to execute an emergency stop, and if the brake pedal is not fully applied, the

system overrides and fully applies the brakes until the Anti-lock Braking System (ABS) takes

over to stop the wheels locking up.

14. Cornering Brake Control systems: Cornering brake control or CBC is

an automotive safety system introduced by carmakers BMW and Mercedes-Benz (ESP

Dynamic Cornering Assist[1] and Curve Dynamic Assist[2]). It is a further development

and expansion of the anti-lock braking system, designed to distribute braking force

during braking whilst cornering.

It works by applying braking pressure asymmetrically despite physically difficult conditions (e.g.

the car swerving towards the inside of the bend when the wheel load changes). By

asymmetrically distributing brake pressure to the left- and right-side brakes or by reducing

pressure (to the rear axle), even if the driver brakes outside the normal range of ABS.

15. Automated parking system: Automatic parking is an autonomous car-maneuvering

system that moves a vehicle from a traffic lane into a parking spot to perform parallel,

perpendicular or angle parking. The automatic parking system aims to enhance the

comfort and safety of driving in constrained environments where much attention and

experience is required to steer the car. The parking maneuver is achieved by means of

coordinated control of the steering angle and speed which takes into account the actual

situation in the environment to ensure collision-free motion within the available space.[1]

The car is an example of a nonholonomic system where the number of control commands

available is less than the number of coordinates that represent its position and orientation.

One of the first assistance systems for car parking was manual. It used four jacks with wheels to

raise the car and then move it sideways into the available parking space. This mechanical system

was proposed in 1934, but was never offered on any production model.

16. Obstacle detection sensor systems notify a driver how close their vehicle is to an object -

usually providing a distance measurement, to the inch, as to how close they are.