Car Safety
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Car Safety? Car safety is the avoidance of car accidents or the minimization of harmful effects of accidents, in particular as pertaining to human life and health. Special safety features have been built into cars for years, some for the safety of car's occupants only, and some for the safety of others. Road traffic injuries represent about 25% of worldwide injury-related deaths (the leading cause) with an estimated 1.26 million deaths in 2000 (Peden 2002). Major factors in accidents include driving under the influence of alcohol or other drugs; inattentive driving; driving while fatigued or unconscious; encounters with road hazards such as snow, potholes, and crossing animals; or reckless driving.
Distance crossed by vehicles in a city (here, Paris) during 1 second (typical time to react to an emergency).
History Car safety became an issue almost immediately after the invention of the automobile, when Nicolas-Joseph Cugnot crashed his steam-powered "Fardier" against a wall in 1771. One of the earliest recorded automobile fatalities was Mary Ward, on August 31, 1869 in Parsonstown, Ireland. 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 1966, the US 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. The NTSB and its European equivalent, EuroNCAP have each issued independent safety tests for all new automobiles, without reciprocity. 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 US. 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 US has about 2 deaths per 10,000 motor vehicles, comparable to 1.9 in Germany, 2.6 in France, and 1.5 in the UK [1]. In 1998 there were 3,421 fatal accidents in the UK, the fewest since 1926 [2]. A much higher number of accidents result in permanent disability.
Colour A Swedish study found pink cars safest, with black cars most likely to be involved in crashes, and also showed Saab to be the "safest car in Sweden [In terms of passive safety]" (Land transport NZ 2005). An Auckland, New Zealand studies found a significantly lower risk of serious injury in silver cars; with high risks for brown, black, and green cars. (Furness et al, 2003). This is probably a coincidence, however, because there has been no way to accurately connect automobiles' colour with safer travel.
Safety Features 23:28, 25 June 2006 (UTC)===Avoidance=== To make driving safer and prevent accidents from occurring, cars may have the following active safety features: • •
•
• •
•
Turn signals and brake lights, including Centre High Mounted Stop Lamps (CHMSL) Anti-lock braking system (ABS) (also Emergency Braking Assistance (EBA), often coupled with Electronic brakeforce distribution (EBD), which prevents the brakes from locking and losing traction while braking. This shortens stopping distances in almost all cases. Inboard brakes allow large fade resistant discs or drums, without contributing to unsprung weight and wheel bounce, which degrade braking, handling and ride, and increase mechanical loads. Traction control (TCS) actuates brakes or reduces throttle to restore traction if driven wheels begin to spin. Four wheel drive (AWD) with a centre differential. 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. 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 numerous manufacturerspecific names). Uses various sensors to intervene when the car senses a possible loss of control. The car's control unit can reduce power from the engine and even apply the brakes to prevent the car from understeering or oversteering. Dynamic steering response (DSR) corrects the rate of power steering system to adapt it to vehicle's speed and road conditions. Lateral Support: Lane Departure Warning System (LDWS). Directional headlights. Low centre of gravity and other conventional features promoting good car handling and braking, and helping to avoid rollover. Large (relative to weight) high performance tires, suited to the weather and road conditions, contribute to braking and handling. Soft high resistant rubber, tread and cord design are important. 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 manoeuvres 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.
Damage control When an accident is imminent, various passive safety systems work together to minimize damage to those involved. Much research has been done using crash test dummies to make modern cars safer than ever. Recently, attention has also been given to cars' design regarding the safety of pedestrians in car-pedestrian collisions. Controversial proposals in Europe would require cars sold there to have a Front drivers-side airbag minimum/maximum hood height. This has caused automakers to complain that the requirements will restrict their design choices, resulting in ugly cars. Others have pointed out that a notable percentage of pedestrians in these accidents are drunk. From 2006, the use of "bull bars" (known as "roo bars" in Australia), in fashion on 4x4s and SUVs, will be illegal. • •
Seatbelts (or safety belts) keep a person from being thrown forward or ejected from the vehicle. Airbags
Front airbags inflate in a medium speed head on collisions to cushion the blow of a head on the dashboard or steering wheel. o Side airbags inflate in a side (T-bone) collision to cushion the torso o Curtain airbags protect the heads of passengers in a side collision Bumpers to withstand low-speed collisions without damaging bodywork. Crumple zones absorb the energy of an impact when the car hits something o Crash box to dissipate impact forces Collapsible steering column sometimes provided with steel sheet bellows. Crash compatibility can be improved by matching vehicles by weight and by matching crumple zones with points of structural rigidity, particularly for side-on collisions. Some pairs of vehicle front end structures interact better than others in crashes. Widely different height and body on rail frame design are particularly bad. Cage construction is designed to protect vehicle occupants. Some racing vehicles have a tubular roll cage Reinforced side door structural members Fuel pump shutoff devices turn off gas flow in the event of a collision for the purpose of preventing gasoline fires. Light weight: the possible damage a vehicle can do to outside people and things are roughly proportional to its kinetic energy, which is its weight times the square of its speed. Active pedestrian protection systems [4]. o
• • • •
• • • •
•
Distance crossed by vehicles in a city (here, Paris) during 1 second (typical time to react to an emergency).
History Car safety became an issue almost immediately after the invention of the automobile, when Nicolas-Joseph Cugnot crashed his steam-powered "Fardier" against a wall in 1771. One of the earliest recorded automobile fatalities was Mary Ward, on August 31, 1869 in Parsonstown, Ireland. 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 1966, the US 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. The NTSB and its European equivalent, EuroNCAP have each issued independent safety tests for all new automobiles, without reciprocity. 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 US. 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 US has about 2 deaths per 10,000 motor vehicles, comparable to 1.9 in Germany, 2.6 in France, and 1.5 in the UK [1]. In 1998 there were 3,421 fatal accidents in the UK, the fewest since 1926 [2]. A much higher number of accidents result in permanent disability.
Colour A Swedish study found pink cars safest, with black cars most likely to be involved in crashes, and also showed Saab to be the "safest car in Sweden [In terms of passive safety]" (Land transport NZ 2005). An Auckland, New Zealand studies found a significantly lower risk of serious injury in silver cars; with high risks for brown, black, and green cars. (Furness et al, 2003). This is probably a coincidence, however, because there has been no way to accurately connect automobiles' colour with safer travel.
Safety Features 23:28, 25 June 2006 (UTC)===Avoidance=== To make driving safer and prevent accidents from occurring, cars may have the following active safety features: • •
•
• •
•
Turn signals and brake lights, including Centre High Mounted Stop Lamps (CHMSL) Anti-lock braking system (ABS) (also Emergency Braking Assistance (EBA), often coupled with Electronic brakeforce distribution (EBD), which prevents the brakes from locking and losing traction while braking. This shortens stopping distances in almost all cases. Inboard brakes allow large fade resistant discs or drums, without contributing to unsprung weight and wheel bounce, which degrade braking, handling and ride, and increase mechanical loads. Traction control (TCS) actuates brakes or reduces throttle to restore traction if driven wheels begin to spin. Four wheel drive (AWD) with a centre differential. 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. 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 numerous manufacturerspecific names). Uses various sensors to intervene when the car senses a possible loss of control. The car's control unit can reduce power from the engine and even apply the brakes to prevent the car from understeering or oversteering. Dynamic steering response (DSR) corrects the rate of power steering system to adapt it to vehicle's speed and road conditions. Lateral Support: Lane Departure Warning System (LDWS). Directional headlights. Low centre of gravity and other conventional features promoting good car handling and braking, and helping to avoid rollover. Large (relative to weight) high performance tires, suited to the weather and road conditions, contribute to braking and handling. Soft high resistant rubber, tread and cord design are important. 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 manoeuvres 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.
Damage control When an accident is imminent, various passive safety systems work together to minimize damage to those involved. Much research has been done using crash test dummies to make modern cars safer than ever. Recently, attention has also been given to cars' design regarding the safety of pedestrians in car-pedestrian collisions. Controversial proposals in Europe would require cars sold there to have a Front drivers-side airbag minimum/maximum hood height. This has caused automakers to complain that the requirements will restrict their design choices, resulting in ugly cars. Others have pointed out that a notable percentage of pedestrians in these accidents are drunk. From 2006, the use of "bull bars" (known as "roo bars" in Australia), in fashion on 4x4s and SUVs, will be illegal. • •
Seatbelts (or safety belts) keep a person from being thrown forward or ejected from the vehicle. Airbags
Front airbags inflate in a medium speed head on collisions to cushion the blow of a head on the dashboard or steering wheel. o Side airbags inflate in a side (T-bone) collision to cushion the torso o Curtain airbags protect the heads of passengers in a side collision Bumpers to withstand low-speed collisions without damaging bodywork. Crumple zones absorb the energy of an impact when the car hits something o Crash box to dissipate impact forces Collapsible steering column sometimes provided with steel sheet bellows. Crash compatibility can be improved by matching vehicles by weight and by matching crumple zones with points of structural rigidity, particularly for side-on collisions. Some pairs of vehicle front end structures interact better than others in crashes. Widely different height and body on rail frame design are particularly bad. Cage construction is designed to protect vehicle occupants. Some racing vehicles have a tubular roll cage Reinforced side door structural members Fuel pump shutoff devices turn off gas flow in the event of a collision for the purpose of preventing gasoline fires. Light weight: the possible damage a vehicle can do to outside people and things are roughly proportional to its kinetic energy, which is its weight times the square of its speed. Active pedestrian protection systems [4]. o
• • • •
• • • •
•
