Braking System

Anti-lock braking system An anti-lock braking system (ABS) (translated from German, Anti-Blockier System) is a safety system on motor vehicles which prevents the wheels from locking while braking. A rotating road wheel allows the driver to maintain steering control under heavy braking, by preventing a locked wheel or skid, and allowing the wheel to continue to forward roll and create lateral control, as directed by driver steering inputs. Disadvantages of the system include increased braking distances under some limited circumstances (ice, snow, gravel, "soft" surfaces), and the creation of a "false sense of security" among drivers who do not understand the operation, and limitations of ABS. Since it came into widespread use in production cars (with "version 2" in 1978), ABS has made considerable progress. Recent versions not only handle the ABS function itself (i.e. preventing wheel locking under braking), but also electronic control of the front-to-rear bias known as electronic brakeforce distribution (EBD), traction control system (TCS or ASR), an "emergency" brake assist (BA, EBA or HBA), and electronic stability control (ESP, ESC or DSC), amongst others.

Contents [hide]

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1 History 2 Operation o 2.1 Additional developments  2.1.1 Traction control 3 Effectiveness 4 Risk compensation 5 Design and selection of components 6 References 7 See also

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8 External links

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[edit] History Anti-lock braking systems were first developed for aircraft in 1929, by the French automobile and aircraft pioneer, Gabriel Voisin, as threshold braking an airplane is nearly impossible. An early system was Dunlop's Maxaret system, introduced in the 1950s and still in use on some aircraft models.

A fully mechanical system saw limited automobile use in the 1960s in the Ferguson P99 racing car, the Jensen FF and the experimental all wheel drive Ford Zodiac, but saw no further use; the system proved expensive and, in automobile use, somewhat unreliable. However, a limited form of anti-lock braking, utilizing a valve which could adjust front to rear brake force distribution when a wheel locked, was fitted to the 1964 Austin 1800.

ABS brakes on a BMW motorcycle Chrysler, together with the Bendix Corporation, introduced a crude, limited production ABS system on the 1971 Imperial. Called "Sure Brake", it was available for several years, and had a satisfactory performance and reliability record. Ford also introduced anti lock brakes on the Lincoln Continental Mark III and the Ford LTD station wagon, called "Sure Trak". The German firms Bosch and MercedesBenz had been co-developing anti-lock braking technology since the 1930s, and introduced the first completely electronic 4-wheel multi-channel ABS system in trucks and the Mercedes-Benz S-Class in 1978. ABS Systems based on this more modern Mercedes design were later introduced on other cars and motorcycles. General Motors introduced the "Trackmaster" ABS on their Cadillac models in 1971 as an option that was operational on the rear wheels for RWD models.[1][2] In 1988 BMW became the world's first motorcycle manufacturer to introduce an electronic/hydraulic ABS system, this on their BMW K100. In 1992 Honda launched its first ABS system, this on the ST1100 Pan European. In 1997 Suzuki launched its GSF1200SA (Bandit) with ABS.

[edit] Operation The anti-lock brake controller is also known as the CAB (Controller Anti-lock Brake). A typical ABS is composed of a central electronic control unit (ECU), four wheel speed sensors (one for each wheel), and two or more hydraulic valves within the vehicle brake circuit. The ECU constantly monitors the rotational speed of each wheel. When it senses that any number of wheels are rotating considerably slower than the others (a condition that is likely to bring it to lock - see note below), it actuates the valves to decrease the pressure on the specific braking circuit for the individual wheel, effectively reducing the braking force on that wheel. The wheel(s) then turn faster; when they turn too fast, the force is reapplied. This process is repeated continuously, and this causes the characteristic pulsing feel through the

brake pedal. A typical anti-lock system can apply and release braking pressure up to 20 times a second. Note: The ECU needs to determine when some of the wheels turn considerably slower than any of the others because when the car is turning the two wheels towards the center of the curve inherently move slightly slower than the other two – which is the reason why a differential is used in virtually all commercial cars. The sensors can become contaminated with metallic dust, or other contaminants, and fail to correctly detect wheel slip; this is not always picked up by the internal ABS controller diagnostic.[citation needed] In this occurrence, the ABS warning light will usually be illuminated on the instrument panel, and the ABS will be disabled until the fault is rectified.

[edit] Additional developments Modern Electronic Stability Control (ESC or ESP) systems are an evolution of the ABS concept. Here, a minimum of two additional sensors are added to help the system work: these are a steering wheel angle sensor, and a gyroscopic sensor. The theory of operation is simple: when the gyroscopic sensor detects that the direction taken by the car does not coincide with what the steering wheel sensor reports, the ESC software will brake the necessary individual wheel(s) (up to three with the most sophisticated systems), so that the vehicle goes the way the driver intends. The steering wheel sensor also helps in the operation of Cornering Brake Control (CBC), since this will tell the ABS that wheels on the inside of the curve should brake more than wheels on the outside, and by how much. [edit] Traction control Main article: Traction control system The ABS equipment may also be used to implement traction control system (TCS, ASR) on acceleration of the vehicle. If, when accelerating, the tire loses traction, the ABS controller can detect the situation and take suitable action so that traction is regained. Manufacturers often offer this as a separately priced option even though the infrastructure is largely shared with ABS.[citation needed] More sophisticated versions of this can also control throttle levels and brakes simultaneously. Mercedes-Benz was the first to offer this electronic traction control system in 1985.

[edit] Effectiveness A 2003 Australian study[3] by Monash University Accident Research Centre found that ABS:

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Reduced the risk of multiple vehicle crashes by 18 percent, Reduced the risk of run-off-road crashes by 35 percent.

On high-traction surfaces such as bitumen, or concrete, many (though not all) ABSequipped cars are able to attain braking distances better (i.e. shorter) than those that would be easily possible without the benefit of ABS. In real world conditions even an alert, skilled driver without ABS would find it difficult, even through the use of techniques like threshold braking, to match or improve on the performance of a typical driver with a modern ABS-equipped vehicle. ABS reduces chances of crashing, and/or the severity of impact. The recommended technique for non-expert drivers in an ABS-equipped car, in a typical full-braking emergency, is to press the brake pedal as firmly as possible and, where appropriate, to steer around obstructions. In such situations, ABS will significantly reduce the chances of a skid and subsequent loss of control. In gravel, sand and deep snow, ABS tends to increase braking distances. On these surfaces, locked wheels dig in and stop the vehicle more quickly. ABS prevents this from occurring. Some ABS calibrations reduce this problem by slowing the cycling time, thus letting the wheels repeatedly briefly lock and unlock. The primary benefit of ABS on such surfaces is to increase the ability of the driver to maintain control of the car rather than go into a skid — though loss of control remains more likely on soft surfaces like gravel or slippery surfaces like snow or ice. On a very slippery surface such as sheet ice or gravel, it is possible to lock multiple wheels at once, and this can defeat ABS (which relies on comparing all four wheels, and detecting individual wheels skidding). Availability of ABS relieves most drivers from learning threshold braking. A June 1999 National Highway Traffic Safety Administration (NHTSA) study found that ABS increased stopping distances on loose gravel by an average of 22 percent.[4] According to the NHTSA, "ABS works with your regular braking system by automatically pumping them. In vehicles not equipped with ABS, the driver has to manually pump the brakes to prevent wheel lockup. In vehicles equipped with ABS, your foot should remain firmly planted on the brake pedal, while ABS pumps the brakes for you so you can concentrate on steering to safety."

When activated, some earlier ABS systems caused the brake pedal to pulse noticeably. As most drivers rarely or never brake hard enough to cause brake lockup, and a significant number rarely bother to read the car's manual, [citation needed] this may not be discovered until an emergency. When drivers do encounter an emergency that causes them to brake hard, and thus encounter this pulsing for the first time, many are believed to reduce pedal pressure, and thus lengthen braking distances, contributing to a higher level of accidents than the superior emergency stopping capabilities of ABS would otherwise promise. Some manufacturers have therefore implemented a brake assist system that determines that the driver is attempting a "panic stop" and the system automatically increases braking force

where not enough pressure is applied. Nevertheless, ABS significantly improves safety and control for drivers in most on-road situations.

[edit] Risk compensation ABS brakes are the subject of some widely cited experiments [citation needed] in support of risk compensation theory, which support the view that drivers adapt to the safety benefit of ABS by driving more aggressively. The two major examples are from Munich and Oslo.[citation needed] In both cases taxi drivers in mixed fleets were found to exhibit greater risk-taking behaviour when driving cars equipped with ABS, with the result that collision rates between ABS and non ABS cars were not significantly different.

[edit] Design and selection of components Given the required reliability, it is illustrative to see the choices made in the design of the ABS system. Proper functioning of the ABS system is considered of the utmost importance, for safeguarding both the passengers within, and people outside of the car. The system is therefore built with some redundancy, and is designed to monitor its own working and report failures. The entire ABS system is considered to be a hard real-time system, while the sub-system that controls the self diagnosis is considered soft real-time. As stated above, the general working of the ABS system consists of an electronic unit, also known as ECU (electronic control unit), which collects data from the sensors and drives the hydraulic control unit (HCU), mainly consisting of the valves that regulate the braking pressure for the wheels. The communication between the ECU and the sensors must happen quickly and at real time. A possible solution is the use of the CAN bus system, which has been, and is still in use in many ABS systems today (in fact, this CAN standard was developed by Robert Bosch GmbH, for connecting electronic control units). This allows for an easy combination of multiple signals into one signal, which can be sent to the ECU. The communication with the valves of the HCU is usually not done this way. The ECU and the HCU are generally very close together. The valves, usually solenoid valves, are controlled directly by the ECU. To drive the valves based on signals from the ECU, some circuitry and amplifiers are needed (which would also have been the case if the CAN-bus was used). The sensors measure the position of the tyres, and are generally placed on the wheelaxis. The sensor should be robust and maintenance free, not to endanger its proper working, for example an inductive sensor. These position measurements are then processed by the ECU to calculate the differential wheel rotation. The hydraulic control unit is generally integrated with the ECU (or the other way around), and consists of a number of valves that control the pressure in the braking

circuits. All these valves are placed closely together, and packed in a solid aluminium alloy block. This makes for a very simple layout, and is thus very robust. The central control unit generally consists of two microcontrollers, both active simultaneously, to add some redundancy to the system. These two microcontrollers interact, and check each other's proper working. These microcontrollers are also chosen to be power-efficient, to avoid heating of the controller which would reduce durability. The software which runs in the ECU has a number of functions. Most notably, the algorithms that drive the HCU as a function of the inputs, or control the brakes depending on the recorded wheel spin. This is the obvious main task of the entire ABS-system. Apart from this, the software also needs to process the incoming information, e.g. the signals from the sensors. There is also some software that constantly tests each component of the ABS system for its proper working. Some software for interfacing with an external source to run a complete diagnosis is also added. As mentioned before the ABS system is considered hard real-time. The control algorithms, and the signal processing software, certainly fall in this category, and get a higher priority than the diagnosis and the testing software. The requirement for the system to be hard real-time can therefore be reduced to stating that the software should be hard real-time. The required calculations to drive the HCU have to be done in time. Choosing a microcontroller that can operate fast enough is therefore the key, preferably with a large margin. The system is then limited by the dynamic ability of the valves and the communication, the latter being noticeably faster. The control system is thus comfortably fast enough, and is limited by the valves.

Electronic brakeforce distribution Electronic brakeforce distribution or EBD is an automobile brake technology that automatically varies the amount of force applied 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.

[edit] How ABS works When a rotating wheel is subjected to excessive heavy braking, it is prone to lockup. In motor vehicles, the anti-lock braking system (ABS) works to prevent this by monitoring wheel speeds and taking action in the form of releasing pressure on the braking circuit, when a rapid deceleration occurs in any of the wheels to ensure steering and vehicular control is maintained during heavy or emergency braking. Modern ABS has four separate channels - one for each tire - as different amounts of braking pressure are required to lock a rotating wheel on different surfaces. For

example, less braking pressure would be needed to lock a wheel which was in contact with ice than a wheel which was in contact with an asphalt road. In a situation where the wheels of a vehicle are on different surfaces (for example the two left wheels are on a concrete road and the two right wheels were on snow), during an emergency stop ABS would detect the two right wheels about to lock and would activate. Less braking force is sent to the right wheels, which would otherwise lock and not slow the car down.

[edit] How EBFD works As per SAE technical paper #920646 - Buschmann et al. "The job of the EBD as a subsystem of the ABS system is to control the effective adhesion utilization by the rear wheels. The pressure of the rear wheels is approximated to the ideal brake force distribution in a partial braking operation. To do so, the conventional brake design is modified in the direction of rear axle overbraking, and the components of the ABS are used. EBD reduces the strain on the hydraulic brake force proportioning valve in the vehicle. EBD optimizes the brake design with regard to: adhesion utilization; driving stability; wear; temperature stress; and pedal force." EBFD works in conjunction with ABS to minimize yaw accelerations during turns. It compares steering wheel angle to a yaw sensor. "Yaw" is the vehicle's rotation about its center of gravity (imagine a car spinning out of control). If the yaw sensor detects more/less yaw than the steering wheel angle should create - the car is understeering or oversteering - EBFD activates one of the rear brakes to rotate the car back into its intended course. The sensors are so sensitive, and the actuation is so quick that the driver doesn't notice it working - or how close he/she was to spinning out and hitting something! For example, if a car is making a left turn, and begins to understeer (the car veers to the outside of the turn) EBFD activates the left rear brake, which will turn the car and make the car point left. Any time you limit power or use brakes to maintain control, you scrub off speed. It is better to have an honestly good handling vehicle than to try to compensate for ill handling properties with electronic devices. A good driver won't invoke this feature in most situations on a race track (although it is useful in those situations), and a street vehicle has no business invoking it on public roads.

Cornering Brake Control Cornering Brake Control or CBC is an automotive safety system developed by BMW.[citation needed] It is a further development and expansion of the anti-lock braking system, designed to distribute braking force during braking whilst cornering. CBC interacts with ABS to counteract oversteer, and generates optimum distribution of

braking effort in corners, keeping the vehicle heading in the intended direction, even if the brakes are applied suddenly.

[edit] Principle of operation Using the revolutions of the wheel, CBC regulates the pressure in the different wheel brake cylinders so that wheels operate separately and brake optimally. In this way the system intervenes early and the driver is unaware of it. In addition, the physically-dependent over-steering while braking on curves is compensated. CBC counteracts these tendencies by modulating brake action at individual wheels in a precise way; for instance, it can cause brake pressure at the outside front wheel to build up more rapidly than at the other wheels. The result is significantly safer and gentler braking. The vehicle remains safe on track at all times. Even during abrupt braking maneuvers, the vehicle remains stable.

Electronic stability control From Wikipedia, the free encyclopedia

Jump to: navigation, search Electronic stability control (ESC) is a computerized technology that improves the safety of a vehicle's handling by detecting and preventing skids. When ESC detects loss of steering control, ESC automatically applies individual brakes to help "steer" the vehicle where the driver wants to go. Braking is automatically applied to individual wheels, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. Some ESC systems also reduce engine power until control is regained.[1]

Contents [hide] • • • • • • • •

1 Operation 2 Components and Design 3 Effectiveness 4 Cost 5 Availability 6 Laws 7 History 8 Future

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9 Product names 10 System Manufacturers 11 See also 12 References

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13 External links

[edit] Operation ESC compares the driver's intended direction, by measuring steering angle, to the vehicle's actual direction, by measuring lateral acceleration, vehicle rotation (yaw) and individual road wheel speeds. If the vehicle is not going where the driver is steering, ESC then brakes individual front or rear wheels and/or reduces engine power as needed to help correct understeer and oversteer. ESC incorporates yaw rate control into the anti-lock braking system (ABS). Yaw is rotation around the vertical axis; i.e. spinning left or right. Anti-lock brakes enable ESC to brake individual wheels. ESC usually also incorporates a traction control system (TCS or ASR), which senses drive-wheel slip under acceleration and individually brakes the slipping wheel or wheels and/or reduces excess engine power until control is regained. ESC cannot override a car's physical limits or increase traction. If a driver pushes the vehicle's traction beyond its limits, ESC cannot prevent a crash. It is a tool to help the driver maintain control using available traction and grip.

[edit] Components and Design The ESC-system uses several sensors to determine what the driver wants (input). Other sensors indicate the actual state of the vehicle (response). The controlalgorithm compares driver input to vehicle response (25 times per second) and decides, when necessary, to apply brakes and/or reduce throttle. The sensors used for ESC have to send data at all times in order to detect possible defects as soon as possible. They have to be resistant to possible forms of interference (rain, holes in the road, etc.). The most important sensors are: •

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Steering wheel angle sensor : determines the driver's intended rotation; i.e. where the driver wants to steer. This kind of sensor is often based on AMRelements. Yaw rate sensor : measures the rotation rate of the car; i.e how much the car is actually turning. The data from the yaw sensor is compared with the data from the steering wheel angle sensor to determine regulating action. Lateral acceleration sensor : often based on the Hall effect. Measures the lateral acceleration of the vehicle.

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Wheel speed sensor : measures the wheel speed.

ESC uses a hydraulic modulator to assure that each wheel receives the correct brake force. A similar modulator is used in ABS. ABS needs to reduce pressure during braking, only. ESC additionally needs to increase pressure in certain situations. The heart of the ESC-system is the Electronic Control Unit (ECU). The various control techniques are embedded in it. Often, the same ECU is used for diverse systems at the same time (ABS, Traction control, climate control, etc.). The input signals are sent through the input-circuit to the digital controller. The desired vehicle state is determined based upon the steering wheel angle, its gradient and the wheel speed. Simultaneously, the yaw sensor measures the actual state. The controller computes the needed brake or acceleration force for each wheel and directs via the driver circuits the valves of the hydraulic modulator. Via a CANinterface the ECU is connected with other systems (ABS, etc.) in order to avoid giving contradictory commands. Most ESC systems use an indicator light on the dash to tell the driver when the system is active (i.e. has detected and corrected skidding). Many ESC systems have an "off" switch so the driver can disable ESC, which may be desirable when badly stuck in mud or snow, or driving on a beach. However, ESC defaults to "On" when the ignition is re-started. Some ESC systems that lack an "off switch", such as on many recent Toyota and Lexus vehicles, can be temporarily disabled through an undocumented series of brake pedal and handbrake operations.[2]

[edit] Effectiveness Numerous studies around the world confirm that ESC is highly effective in helping the driver maintain control of the car and saving lives and reducing the severity of crashes.[3] In the fall of 2004 in the U.S., the National Highway and Traffic Safety Administration confirmed the international studies, releasing results of a field study in the U.S. of ESC effectiveness. NHTSA concluded that ESC reduces crashes by 35%. Additionally, Sport utility vehicles (SUV's) with stability control are involved in 67% fewer accidents than SUVs without the system. The Insurance Institute for Highway Safety (IIHS) issued its own study results in 2004 concluding that universal use of ESC could save 7,000 lives a year in the United States. In June 2006, the IIHS released a second study showing that up to 10,000 fatal US crashes could be avoided annually if all vehicles were equipped with ESC[4] The 2006 study concluded that ESC reduces the likelihood of all fatal crashes by 43%, fatal single-vehicle crashes by 56%, and fatal single-vehicle rollovers by 77-80%. ESC is described as the most important advance in auto safety since the seat belt by many experts[5] including Nicole Nason,[6] Administrator of the NHTSA,[7] Jim Guest and David Champion[8] of Consumers Union[9] Max Mosley of the Fédération

Internationale de l'Automobile (FIA), E-Safety Aware[10], Csaba Csere, editor of Car and Driver[11], and Bill Kozyra, CEO of Continental Automotive Systems[7].The European New Car Assessment Program (EuroNCAP) "strongly recommends" that people buy cars fitted with stability control.[12] On November 21, 2006 the IIHS announced that 13 of the 2007 vehicles had earned its TOP SAFETY PICK rating which is based primarily on crashworthiness; however, a major new requirement for this top rating is that the vehicle must be equipped with ESC (which helps avoid crashes)[13]. The NHTSA issued a final research report in July 2007, stating, "ESC reduced all fatal crashes by 14% for passenger cars and 28% for LTVs (Light Trucks and Vans). Only the reduction in LTVs is statistically significant." Although that data was not statistically significant for passenger cars generally, it was found to be statistically significant that "policereported crash involvements decreased by 8% in passenger cars and 10% in LTVs." [14] .

[edit] Cost ESC is built on top of an anti-lock brake (ABS) system. The ESC components include a Yaw rate sensor, a Lateral Acceleration Sensor, a Steering Wheel Sensor, and an upgraded Integrated Control Unit. According to National Highway Traffic Safety Administration research, ABS costs an estimated US$368 (in 2005) and ESC costs an additional US$111. The retail price of ESC varies; as a stand-alone option, it retails for as little as $450. Unfortunately, many auto makers bundle ESC with other features so the cost of a package that includes ESC could be several thousands of dollars. ESC is highly cost-effective[15] and it might pay for itself in reduced insurance premiums.[16]

[edit] Availability ESC is not generally available for after-market installation. The only way consumers can get ESC is to buy a vehicle equipped by the manufacturer with standard or optional ESC. Availability of ESC in passenger vehicles varies between manufacturers and countries. In 2007, ESC was available in roughly 50% of new North American models, whereas that figure is about 75% in Sweden. However, consumer awareness affects buying patterns so that roughly 45% of vehicles sold in North America and the UK are purchased with ESC[17], contrasting with 78-93% in other European countries such as Germany, Denmark, and Sweden. While few vehicles had ESC prior to 2004, increased awareness will increase the number of vehicles with ESC on the used car market.

ESC is available on cars, SUV's, and pickup trucks from all major auto makers. ESC is also available on some motor homes. Elaborate ESC and ESP systems (including Roll Stability Control (RSC)[18]) are available for many commercial vehicles[19], including transport trucks, trailers, and buses from manufacturers such as Bendix Corporation[20], WABCO [21], Daimler,[22], Scania AB[23], and Prevost[24] The Insurance Institute for Highway Safety (IIHS) website[25] shows availability of ESC in individual US models and the National Highway Traffic Safety Administration (NHTSA website[26] lists US models with ESC. The National Roads and Motorists' Association NRMA shows availability of ESC in Australian models.[27] CHOOSE ESC! shows availability of ESC in European countries[28]

[edit] Laws While Sweden used public awareness campaigns to promote ESC use, [29] others implemented or proposed legislation. Quebec was the first jurisidiction to implement an ESC law, making it mandatory for carriers of dangerous goods (without data recorders) in 2005.[30] The United States was next, mandating ESC for all passenger vehicles under 10,000 pounds (4536 kg), phasing in the regulation starting with 55% of 2009 models, 75% of 2010 models, 95% of 2011 models, and 100% of 2012 models.[31] Australia [32] and Canada[33][34] will likely be next, requiring 100% of passenger vehicles to have ESC on September 1, 2011, matching the U.S. The United Nations Economic Commission for Europe is working on a Global Technical Regulation to harmonize standards for ESC.[35]

Automobile safety From Wikipedia, the free encyclopedia

Jump to: navigation, search "Passive safety" redirects here. For nuclear safety, see Passive nuclear safety. Automobile safety is the avoidance of automobile accidents or the minimization of harmful effects of accidents, in particular as pertaining to human life and health. Numerous safety features have been built into cars for years, some for the safety of car's occupants only, some for the safety of others.

Distance covered by vehicles in one second. As a result of improvements in highway and automobile design, the incidence of injuries and fatalities per mile driven has decreased significantly, but road traffic injuries still represent about 25% of worldwide injury-related deaths (the leading cause) with an estimated 1.2 million deaths (2004) each year - World Health Organization [1]). Major factors in accidents include driving under the influence of alcohol or other drugs; inattentive driving; crash compatibility between vehicles; driving while fatigued or unconscious; encounters with road hazards such as snow, potholes, and crossing animals; or reckless driving.

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1 History 2 Passenger safety o 2.1 Pregnant women o 2.2 Children  2.2.1 Infants  2.2.1.1 Infants left in cars  2.2.2 Toddlers  2.2.3 Young children  2.2.4 Older children  2.2.5 Teenage drivers 3 Safety features o 3.1 Active safety o 3.2 Passive safety o 3.3 Pedestrian safety o 3.4 Color 4 See also

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5 References

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6 External links

[edit] History Car safety may have become an issue almost from the beginning of mechanised road vehicle development. The second steam-powered "Fardier" (artillery tractor), created by Nicolas-Joseph Cugnot in 1771, is reported by some to have crashed into a wall during its demonstration run. However according to Georges Ageon [2], the earliest mention of this occurrence dates from 1801 and it does not feature in contemporary accounts. One of the earliest recorded automobile fatalities was Mary Ward, on August 31, 1869 in Parsonstown, Ireland. In the 1930s, plastic surgeon Claire L. Straith and physician C. J. Strickland advocated the use of seat belts and padded dashboards. Strickland founded the Automobile Safety League of America [3][4]. In 1934 GM performed the first barrier crash test.[5] 1944 Volvo introduced the first safety cage to modern cars but it was patented by Mercedes Benz before Volvo. In 1949 SAAB incorporated aircraft safety thinking into automobiles making the Saab 92 the first production SAAB car with a safety cage[6]. In 1942 Hugh De Haven published the classic Mechanical analysis of survival in falls from heights of fifty to one hundred and fifty feet. [7] In the 1950s, Mercedes-Benz extensively crash tested prototypes.[8]. Volvo was the first company to produce cars with padded dashboards starting in late 1956 with their Amazon model. In 1958, the United Nations established the World Forum for Harmonization of Vehicle Regulations, an international standards body advancing auto safety. Many of the most life saving safety innovations, like seat belts and roll cage construction were brought to market under its auspices. In 1958, Volvo engineer Nils Bohlin invented and patented the modern 3-Point Safety Belt, which became standard on all Volvo cars in 1959. The three point safety belt was made standard on all cars. In 1966, the U.S. established the United States Department of Transportation (DOT) with automobile safety one of its purposes. The National Transportation Safety Board (NTSB) was created as an independent organization on April 1, 1967, but was

reliant on the DOT for administration and funding. However, in 1975 the organization was made completely independent by the Independent Safety Board Act (in P.L. 93-633; 49 U.S.C. 1901). Volvo developed the first rear-facing child seat in 1964[14] and introduced its own booster seat in 1978. The NTSB and its European equivalent, EuroNCAP have each issued independent safety tests for all new automobiles, without reciprocity. In 1984, New York State passed the first law requiring seat belt use in passenger cars. Seat belt laws have subsequently been adopted by all 50 states[9], and NHTSA estimates that seat belt laws save 10,000 per year in the USA[10]. In 1986, Volvo introduced the first central high-mounted stoplight[16] (a brake light not shared with the rear tail lights), which became federally mandated in the United States in the 1986 model year. In 1998 Volvo also developed and was the first to install a head protecting airbag, which was made standard in all new models as well as some existing models. In June, 2004 the NTSB released new tests designed to test the rollover risk of new cars and SUVs. Only the Mazda RX-8 got a 5-star rating. However, the correlation between official crash test results and road deaths in vehicles is not exact. An alternative method of assessing vehicle safety is to study the road accident statistics on a model-by-model basis. Despite technological advances, the death toll of car accidents remains high: about 40,000 people die every year in the U.S. While this number increases annually in line with rising population and increased travel, the rate per capita and per vehicle miles travelled decreases. In 1996 the U.S. had about 2 deaths per 10,000 motor vehicles, comparable to 1.9 in Germany, 2.6 in France, and 1.5 in the UK [11]. In 1998 there were 3,421 fatal accidents in the UK, the fewest since 1926.[12] A much higher number of accidents result in permanent disability.

[edit] Passenger safety [edit] Pregnant women When pregnant, women should continue to use seatbelts and airbags properly. A University of Michigan study found that "unrestrained or improperly restrained pregnant women are 5.7 times more likely to have an adverse fetal outcome than properly restrained pregnant women". [13] If seatbelts are not long enough, extensions are available from the car manufacturer or an aftermarket supplier.

[edit] Children Car safety is especially critical for young children, as car safety is generally designed for normal sized adults. Safety features that could save an adult can actually cause more damage to a child than if the feature was not there. It is important to review with others, who may be supervising the child, the rules for car safety. All children age 12 and under should ride in the back seat. Also children weighing less than 85 lb (40 kg) should be in the back seat. This is especially the case if there are airbags in the front seat, as airbags are only designed to protect adults and may injure children; since airbags inflate at high speeds, a child who is improperly seated may be hit by an inflating airbag. That is not just an opinion but is also law in many of the U.S. states and other countries. The Center for Injury Research and Prevention at The Children's Hospital Of Philadelphia has developed a website for parents and caregivers with extensive information about transporting children safely in automobiles. Child safety locks prevent children from accidentally opening doors from inside the vehicle, even if the door is unlocked. The door, once unlocked, can then be opened only from the outside. To find out more about laws relating to children car safety contact your local department of transportation authority. [edit] Infants Newborn babies should be put in a car seat until they weigh at least 20 or 22 pounds (10 or 11 kg). These carriers are designed to be placed in the rear seat and face towards the rear with the baby looking towards the back window. Some of these carriers are "Convertibles" which can also be used forward facing for older children. With infants, these should only be used facing the rear. Harness straps should be at or below shoulder level. A rear-facing infant restraint must never be put in the front seat of a vehicle with a front passenger air bag. A rear-facing infant restraint places an infant's head close to the air bag module, which can cause severe head injuries or death if the air bag deploys. Modern cars include a switch to turn off the airbag system of the passenger seat, in which case a child-supporting seat must be installed.

[edit] Infants left in cars Less has been written about the safety hazard of leaving a child in a parked car, but already two advocacy groups have emerged focusing on separate aspects of the problem: Harrison's Hope[14] reminds parents never to leave a child in a car to run an errand, while KidsandCars.org[15] has pointed out the problem of absent-minded parents.[16] An informal parenting poll[17] shows that the majority of parents have left their kids unattended in a car. [edit] Toddlers

Toddlers over 1 year old and between 10 and 20 kg (20 and 40 pounds) should remain in a rear-facing child restraint until they have reached either the maximum allowable weight for the seat, or the tops of the toddler's head is less than 1" away from the top of the hard shell of the seat. Once that has been reached, then the toddler can be placed in an appropriate forward-facing child restraint. [edit] Young children Children who weigh from 40 to 80 pounds (35 kg), are younger than 8, or are shorter than 4 ft 9 in (1.4 m) are advised to use booster seats, which raise them to a level that allows the seat belts to work effectively. These seats are forward facing and must be used with both lap and shoulder belts. Make sure the lap belt fits low and tight across the lap/upper thigh area and the shoulder belt fits snug crossing the chest and shoulder to avoid abdominal injuries. There are two main types of booster seats. If the car's back seat is lower than the child's ears, a high back booster seat should be used to help protect the child's head and neck. If the car's seat back is higher than the child's ears, a backless booster seat can be used. [edit] Older children Children who can sit erect with their back flat against the back of a vehicle's rear seat, and whose legs bend comfortably at the knee at the edge of the seat can wear ordinary seatbelts. Be sure the shoulder strap fits snugly across the chest and that the lap belt is placed below the abdomen across the pelvis at the top of the thighs. Children 13 and over can ride up front with little danger from an airbag. [edit] Teenage drivers In the UK you can get a full driving license aged 17 whereas most areas in the United States will issue a full driver's license at the age of 16, and all within a range between 14 and 18. [18] In addition to being relatively inexperienced, teen drivers are also cognitively immature, compared to other drivers.[19] This combination leads to an increased risk of accidents among this demographic.[20] It is also recommended, and required in some areas, that new drivers stick a printed sign with the words "Novice Driver" in the lower driver's side corner of the rear window. This is to alert other drivers that the vehicle is being driven by an inexperienced and learning driver, giving them opportunity to be more cautious and to encourage other drivers to give novices more leeway.[21] Some countries, such as Australia, the United States, Canada and New Zealand, have graduated levels of driver's licence, with special rules[22].

[edit] Safety features

Active safety refers to vehicle systems that use information about a vehicle's external environment to change the response of the vehicle and improve the safety of the vehicle in the pre-crash time period or during the crash event, with the ultimate goal of avoiding a crash altogether. Active safety includes both autonomous systems, such as RADAR-based crash avoidance systems, and cooperative systems that rely on vehicle-to-vehicle and vehicle-to-infrastructure (and vice versa) communication. Cooperative systems have been the focus of the national Vehicle Infrastructure Integration (VII) program. Passive safety refers to built-in features of a vehicle, such as crumple zones, seatbelts, and airbags, that work passively to prevent injury and do not change the vehicle's action in response to crash scenario or severity.

[edit] Active safety Active safety features make driving safer and prevent crashes from occurring. Active safety features include: •

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Intelligent speed adaptation which physically prevents vehicles from being able to exceed the speed limit through electronic throttle control governed by a GPS matched database of speed limits. Turn signals and brake lights, including Center High Mounted Stop Lamps (CHMSL) Rear end Collision Warning Lamps senses deceleration of lead vehicle and flashes amber warning strobe rearward to warn following vehicles of a pending braking or stopping event Variable assist power steering allows assistance to the motorist while parking, but reduces steering effort assistance at motorway speeds Headlight wipers/washers Mercedes-style ribbed tail lights to prevent snow and grime build-up Dynamic steering response (DSR) corrects the rate of power steering system to adapt it to vehicle's speed and road conditions. Traction control (TCS) actuates brakes or reduces throttle to restore traction if driven wheels begin to spin. Hill holder. Four wheel drive (AWD). Distributing power to all four wheels lessens the chances of wheel spin. It also suffers less from oversteer and understeer than front wheel drive, but more understeer than rear wheel drive. However, some four wheel drive vehicles (particularly SUVs have a higher center of gravity and are more prone to roll-over and cause injury or death to passengers. Reverse backup sensors, which alert drivers to nearby objects in their path, are installed in some high-end vehicles, but may also be purchased separately. Electronic Stability Control (ESC, also known by ESP and other numerous manufacturer-specific names). Uses various sensors to intervene when the car senses a possible loss of control. The car's control unit can reduce power from

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the engine and even apply the brakes to prevent the car from understeering or oversteering. See car stability Lateral Support : Lane Departure Warning System (LDWS). Directional headlights, which allow the driver to see obstacles ahead in the roadway while cornering. Low center of gravity and other conventional features promoting good car handling and braking, and helping to avoid rollover. Comfortable suspension and seating to avoid accidents from driver fatigue. Large (relative to weight) high performance tires, suited to the weather and road conditions, contribute to braking and handling. Soft high histeresis rubber, tread and cord design are important. See Run flat tire. Visibility for the driver, mirrors, elimination of blind spots and possibly other awareness aids such as radar, wireless vehicle safety communications and night vision. Death Brake; there is a move to introduce deadman's braking into automotive application, primarily heavy vehicles, there may also be a need to add penalty switches to cruise controls. Four wheel steering gives, at the cost of mechanical complexity, quicker, more accurate maneuvers at high speed and/or decreased turning circle at low speed. It may also help stability. Adaptive cruise control (ACC). AWAKE and intelligent car features. Precrash system Seatbelts might also play a minor role in active safety by keeping (via locking of the inertial reel) the driver firm on his/her seat in a high-g turn or deceleration. This has been further developed and patented by MercedesBenz in the PreSafe technology which provides a synergy between active and passive systems, helping the driver avoid a danger and preparing him/her for an imminent crash.