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.
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 ).
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.
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 , 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 .
In 1934 GM performed the first barrier crash test.
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.
In 1942 Hugh De Haven published the classic Mechanical analysis of survival in falls from heights of fifty to one hundred and fifty feet.
In the 1950s, Mercedes-Benz extensively crash tested prototypes..
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 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, and NHTSA estimates that seat belt laws save 10,000 per year in the USA.
In 1986, Volvo introduced the first central high-mounted stoplight (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 . In 1998 there were 3,421 fatal accidents in the UK, the fewest since 1926.
A much higher number of accidents result in permanent disability.
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"
. If seatbelts are not long enough, extensions are available from the car manufacturer or an aftermarket supplier.
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.
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.
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 reminds parents never to leave a child in a car to run an errand, while KidsandCars.org has pointed out the problem of absent-minded parents. An informal parenting poll shows that the majority of parents have left their kids unattended in a car.
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.
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.
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
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. In addition to being relatively inexperienced, teen drivers are also cognitively immature, compared to other drivers. This combination leads to an increased risk of accidents among this demographic.
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.
Some countries, such as Australia, the United States, Canada and New Zealand, have graduated levels of driver's licence, with special rules.
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.
Active safety features make driving safer and prevent crashes from occurring. Active safety features include:
- 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 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 hysteresis 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 Mercedes-Benz 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.
Passive safety refers to when a crash is imminent or actually happening, various passive safety systems work together to minimize injury to the individuals involved. Much research has been done using crash test dummies to make modern cars safer than ever.
- Seatbelts (or safety belts) absorb energy and limit forward motion of an occupant, and help keep occupants from being ejected from the vehicle.
- Shoulder harnesses add additional protection to seatbelts by restraining the upper body, absorbing energy and preventing injuries from second collisions where the moving occupant hits the stationary dashboard or windshield.
- Energy absorbing windshields. Beginning in 1966, windshields in cars sold in the US have had a deformable polymer layer that allows the windshield to deform on impact absorbing energy and preventing penetration of the head through the windshield.
- Airbags: There are many types of airbags, all of which should be considered supplemental restraint systems (SRS), used in addition to belts.
- Front airbags inflate in a medium speed head on collision to cushion the impact of the head to the steering wheel (driver) or dashboard to the (front passenger) .
- Side airbags inflate in a side impact (T-bone) collision to cushion the torso and sometimes the pelvis and head.
- Curtain airbags protect the head and upper body of passengers in a side collision. Newer models may stay inflated for a longer period of time, and may help to keep unbelted occupants in vehicle during a rollover, but should be considered supplemental to belts and never used in place of belts.
- Knee airbags inflate in frontal impact collisions to protect the driver's knees and are now available in many newer high end model vehicles.
- Crumple zone technology absorbs the energy of a collision by displacing the impact of a crash and diverting it from the internal (passenger compartment) critical structure of the vehicle.
- Side impact bars for protection against side on collisions
- 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.
- Cage construction is designed to protect vehicle occupants. Some racing vehicles have a tubular roll cage
- Reinforced side door structural members
- Door handles secure enough for emergency occupant extrication through a winch.
- Fuel pump shutoff devices turn off gas flow in the event of a collision for the purpose of preventing gasoline fires.
- Active pedestrian protection systems.
- Driver State Sensor - The system measures 3D head pose and eyelid motion parameters of the driver.
- Padding of the instrument panel and other interior parts of the vehicle likely to be struck by the occupants during a crash. Whilst largely being supplanted by airbags, it still plays an important role in preventing injuries.
Since at least the early 1970s, attention has also been given to vehicle design regarding the safety of pedestrians in car-pedestrian collisions. Proposals in Europe would require cars sold there to have a minimum/maximum hood (bonnet) height. From 2006 the use of "bull bars", a fashion on 4x4s and SUVs, became illegal. unless approved
A Swedish study found that pink cars are involved in the fewest accidents, with black cars being most often involved in crashes (Land transport NZ 2005).
In Auckland New Zealand, a study found that there was a significantly lower rate of serious injury in silver cars; with higher rates in brown, black, and green cars. (Furness et al, 2003)
The Vehicle Color Study, conducted by Monash University Accident Research Centre (MUARC) and published in 2007, analysed 855,258 accidents occurring between 1987 and 2004 in the Australian states of Victoria and Western Australia that resulted in injury or in a vehicle being towed away . The study analysed risk by light condition. It found that in daylight black cars were 12% more likely than white to be involved in an accident, followed by grey cars at 11%, silver cars at 10%, and red and blue cars at 7%, with no other colors found to be significantly more or less risky than white. At dawn or dusk the risk ratio for black cars jumped to 47% more likely than white, and that for silver cars to 15%. In the hours of darkness only red and silver cars were found to be significantly more risky than white, by 10% and 8% respectively.
- Furness, Sue, J Connor, E Robinson, R Norton, S Ameratunga, R Jackson Car colour and risk of car crash injury: population based case control study.. British Medical Journal 327:1455–1456. BMJ Publishing Group. (2003-12-20). Retrieved on 2006-01-01..
- IEEE Communications Magazine, April 2005, "Ad Hoc Peer-to-Peer Network Architecture for Vehicle Safety Communications"
- IEEE Communications Magazine, April 2005, "The Application-Based Clustering Concept and Requirements for Intervehicle Networks"
- Safe vehicle colours.. Land transport NZ. (2005). Retrieved on 2006-01-01..
- Peden M, McGee K, Sharma G. The injury chart book: a graphical overview of the global burden of injuries.. Geneva, World Health Organization. (2002). Retrieved on 2006-01-01.. ISBN 92-4-156220-X
- Physics Today, January 2006, "Vehicle Design and the Physics of Traffic Safety"
- Car Safety Equipment - Frontal and Side car crash video in slow motion
- Teen Safe Driver - Drive Cam
- Vehicle Safety Site
- European safety ratings
-  European vs US roof strength
- American safety ratings
- National Transportation Safety Board (USA)
- California Highway Patrol booster seat webpage
- Vehicle Research Center
- Safety Research & Strategies, motor vehicle safety
- truck safety and statistics
- Child Passenger Safety Resource
- Insurance Institute for Highway Safety Status Report Newsletters
- 2007 Used Car Safety Rating Report
- State Child Restraint Requirement
- National agency for Automotive Safety & Victim's Aid (NASVA), Japan
- Website about crash test results