Traffic collision

In an accident resulting from excessive speed, this concrete truck rolled over into the front garden of a house. There were no injuries, but significant damage was caused.

A car accident, sometimes called a car crash or car wreck, is an incident in which an automobile collides with anything that causes damage to the automobile, including other automobiles, telephone poles, buildings or trees, or in which the driver loses control of the vehicle and damages it in some other way, such as driving into a ditch or rolling over. Sometimes a car accident may also refer to an automobile striking a human or animal. Car crashes — also called road traffic accidents (RTAs), traffic collisions, auto accidents, road accidents, personal injury collisions, motor vehicle accidents (MVAs), — kill an estimated 1.2 million people worldwide each year, and injure about forty times this number (WHO, 2004).

Causes

See also: Road-traffic safety

Many countries require the reporting and collection of road traffic accident statistics. Although the type of information collected differs between jurisdiction, this enables a figure to be produced for personal injuries and deaths to be produced, and correlated against a range of circumstances. It is then possible to attempt to group these circumstances in order to infer a cause, or causes for sets of accidents.

It has long been recognised that there may be a combination of factors, such as road conditions, weather environment, driver actions, or pedestrian actions, that contribute to an accident or road death. For example, an early study by John Leeming, then responsible for the road network of the English county of Dorset, compared the circumstances around road deaths as reported in various American states (before the widespread introduction of 55 mph speed limits and drink-driving laws):

'They took into account thirty factors which it was thought might affect the death rate. Among these were included the annual consumption of wine, of spirits and of malt beverages — taken individually — the amount spent on road maintenance, the minimum temperature, certain of the legal measures such as the amount spent on police, the number of police per 100,000 inhabitants, the follow-up programme on dangerous drivers, the quality of driver testing, and so on. The thirty factors were finally reduced to six on elimination of those which were found to have small or negligible effect. The final six were:

• (a) The percentage of the total state highway mileage that is rural.
• (b) The per cent increase in motor vehicle registration.
• (c) The extent of motor vehicle inspection.
• (d) The percentage of state-administered highway that is surfaced.
• (e) The average yearly minimum temperature.
• (f) The income per capita.

'These are placed in descending order of importance. These six accounted for 70% of the variations in the rate.'

As the factors involved in collisions have been better understood, the term "accident" is sometimes avoided by some organisations.

Road design

As the understanding of these contributory factors have improved, there have been attempts to mitigate the worse of the physical road conditions, which can now include:

• road improvements, with redesigned junctions and grade separated interchanges, and through-traffic bypassing pedestrian areas
• rest areas and motorway service stations
• clear signage and signals for road users and pedestrians
• wide multi-lane roads with divided carriageways
• treatments of the road surface to improve skid resistance, such as applying special mastics at identified accident 'black spots' or road drains and grooving for rainwater runoff
• calming traffic in potentially hazardous areas to reduce the risk of collisions and to minimise the severity of injuries

Vehicle design and maintenance

A well-maintained vehicle, with good brakes, tyres and well-adjusted suspension will be more controllable in an emergency and thus be better equipped to avoid collisions. Some mandatory vehicle inspection schemes test for roadworthiness, such as the UK's MOT test.

The design of vehicles has also evolved to improve protection after collision. Initially this was as a result of consumer pressure, after publications such as Ralph Nader's Unsafe at Any Speed, and more latterly under government legislation, such as the Euro NCAP impact test. On close inspection, modern vehicles show design features such as thicker pillars, safety glass, and interiors with no sharp edges. Less obvious are the stronger bodies and other active or passive safety features. They also feature smooth exteriors to reduce the consequences of an impact with unprotected pedestrians.

In the UK the Department of Transport publishes road death statistics for each type of vehicle. These statistics show a ten to one ratio of in-vehicle accident deaths between types of car. In most cars, occupants have a 2–8% chance of death in a two-car accident.

At the other extreme, motorcyclists have little protection other than their clothing; this difference is reflected in the death and accident statistics. In 2005 in there were 198,735 road accidents with 271,017 reported casualties on roads in Great Britain. This included 3,201 deaths (1.1%) and 28,954 serious injuries (10.7%) overall. Of these casualties 178,302 (66%) were car users and 24,824 (9%) were motorcyclists, of whom 569 were killed (2.3%) and 5,939 seriously injured (24%).

Some types of accident tend to have more serious consequences; rollovers are much more common in older SUVs as compared to passenger cars because of their top weight. This can often be fatal, especially if the occupants are ejected because they were not wearing seat belts. Newer SUVs, such as the Jeep Grand Cherokee SRT8, have a lower center of gravity and enhanced stability control which lowers the risk of rollover substantially.

Driver behaviour

Accompanying the changes to road designs has been been a wide-scale adoption of law enforcement policies, including drink-driving laws, widespread setting of speed limits, speed enforcement systems such as speed cameras, with the intention of averting or reducing the severity of collisions. Some countries' driving tests have been expanded to test a new driver's behaviour during emergencies and hazard perception.

Leeming warned of being too dogmatic in the imposition of traffic policies and noted that there is a balance to be struck when "improving" the safety of a road:

It can safely be said that places which look dangerous do not have accidents, or very few. They happen at places which do not look dangerous. The reason for this is simple. The motorist is as intelligent as the 'local people'. If a place looks dangerous, he can see that it is, so he takes care and there are no accidents. He does not want to have an accident, and he will take care at obviously dangerous places. Accidents happen when there is some trap in road conditions which is not obvious at a glance, or where the conditions are too complicated for the limited human machine to deal with in the short time available. The driver has only a fraction of a second to size up a situation, and there may be some trap which he cannot see in this short time.'

Thus a key part of Woonerf and Shared space urban traffic schemes is the introduction of a street environment and design that encourages the road user to be aware of potential hazards by interacting with other pedestrian and road traffic, and naturally negotiate a safe style of driving.

Driver impairment

A road user's capability is affected by the physical and mental ability to assess conditions and respond quickly. Studies have established some common conditions that impair this judgement, including:

• poor eyesight and/or physical impairment, with many jurisdictions setting simple sight tests and/or requiring appropriate vehicle modifications before being allowed to drive
• old age, with some jurisdictions requiring driver retesting for reaction speed and eyesight after a certain age
• tiredness
• excessive alcohol, with simple blood-alcohol limits enforced through drink-driving laws (although some level of impairment may occur below the legal limit)
• drug use - including some prescription drugs, over the counter drugs (notably antihistamines, opioids and muscarinic antagonists), and illegal drugs.

Multiple conditions can work together to create a much worse situation, for example;

• combining low doses of alcohol and cannabis has a more severe effect on driving performance than either cannabis or alcohol in isolation, or
• taking recommended doses of several drugs together, which individually will not cause impairment, may combine to bring on drowsiness or other impairment. This could be more pronounced in an elderly person whose renal function is less efficient.

Thus there are situations when a person may be impaired, but still legally allowed to drive, and becomes a potential hazard to themselves and other road users. Pedestrians or cyclists are affected in the same way and can similarly jeopardise themselves or others when on the road.

Recent research conducted by British scientists suggests that the driver's attention is affected by distracting sounds. For instance, classic music is considered to be calming, yet too much could calm the driver to a condition of distraction. On the other hand, hard-rock encourages the driver to step on the acceleration pedal, thus creating a potentially dangerous situation on the road.

Death and injury statistics

The ability to deliver prompt medical attention has also improved through improvements in ambulance and rescue equipment, availability of air ambulances, rapid response units, and paramedic training, while design changes have made collisions more survivable. Thus injuries from a collision that once would have been fatal may now be averted, while remote locations may report few accidents but with more fatalities.

For this reason modern accident statistics often focus on reportable injury accidents (which includes deaths) rather than reporting on deaths alone. Local differences in requirements for reporting can sometimes make international comparisons of figures difficult.

Trends in collision statistics

A Chevrolet Malibu involved in a rollover crash

Road toll figures show that car collision fatalities have declined since 1980, with most countries showing a reduction of roughly 50%. This drop appears to confirm the efficacy of safety measures introduced thereafter, assuming that driver behaviour has not changed significantly.

File:Img0a36.jpg

A moderate head-on collision involving a Perodua Kancil and an old Mitsubishi Lancer in a village.

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The driver of this Honda Accord was under the influence of alcohol and drove into a small guard house in Malaysia.

In the United States, fatalities have increased slightly from 40,716 in 1994 to 42,884 in 2003. However, in terms of fatalities per 100 million miles driven, the fatality rate has dropped 16% between 1995 and 2005. Injuries dropped 37% over the same period. (National Traffic Safety Administration, 2006). In addition, there are many variables that have been shown to statistically correlate to car accidents, including: drunk driving, road type, age of driver, and gasoline prices.

It has been noted that road fatality trends closely follow the so-called "Smeed's law" (after RJ Smeed, its author), an empirical rule relating injury rates to the two-thirds power of car ownership levels. An analysis by John Adams can be found here.

Legal consequences

Car collisions usually carry legal consequences in proportion to the severity of the crash. Nearly all common law jurisdictions impose some kind of requirement that parties involved in a collision (even with only stationary property) must stop at the scene, and exchange insurance or identification information or summon the police. Failing to obey this requirement is referred to as hit and run and is generally a criminal offence. Most car claims are settled without using an attorney.

Parties involved in an incident may face criminal liability, civil liability, or both. Usually, the state starts a prosecution only if someone is severely injured or killed, or if one of the drivers involved was clearly grossly negligent or intoxicated or otherwise impaired at the time the accident occurred. Charges might include driving under the influence of alcohol or drugs, assault with a deadly weapon, manslaughter, or murder; penalties range from fines to jail time to prison time to death (although the death penalty is not applicable in many jurisdictions). It is notable that the penalties for killing and injuring with motor vehicles are often very much less than for other actions with similar outcomes.

As for civil liability, automobile accident personal injury lawsuits have become the most common type of tort. Because these cases have been litigated often in the developed First World nations, the legal questions usually have been answered in prior judgments. So, the courts usually need to decide only the factual questions of who is at fault, and their percentage of fault, as well as how much must be paid out in damages to the injured plaintiff by the defendant's insurer.

Another element of liability involves the administrative fines or license suspension/revocation that may be imposed by civil or criminal authorities when a driver has violated the rules of the road and thus the terms of a driver's license. Such complaint may be filed by a police officer or sometimes by other witnesses of an incident. In some jurisdictions such administrative penalties, may be imposed through quasi-criminal infractions; other jurisdictions do not recognize infractions and charge all violations, at a minimum, as misdemeanours or felonies.

Backup collisions

Backup collisions happen when a driver reverses the car into an object, person, or other car. Although most cars come equipped with rear view mirrors which are adequate for detecting vehicles behind a car, they are inadequate on many vehicles for detecting small children or objects close to the ground, which fall in the car's blind spot. Large trucks have much larger blind spots that can hide entire vehicles and large adults.

According to research by Kids and Cars – an organization devoted to preventing (non-traffic) motor-vehicle-related deaths and injuries – 49% of the non-traffic, non-crash fatalities involving children under 15 from 2001–2005 were caused by vehicles backing up.

The CDC reported that from 2001–2003, an estimated 7,475 children (2,492 per year) under the age of 15 were treated for automobile back-over incidents.

In its “Deaths and Injuries Resulting from Certain Non-Traffic and Non-Crash Events,” report issued in May of 2004, the National Highway Traffic Safety Administration found that back-up collisions most often:

• Occur in residential driveways and parking lots
• Involve sport utility vehicles (SUVs) or small trucks
• Occur when a parent, relative or someone known to the family is driving
• Particularly affect children less than five years old

The driver of the car backing up and hitting an object, a person, or another car is usually considered to be at fault.

Prevention organizations suggest that parents use common sense, and also take safety measures such as installing cross view mirrors, audible collision detectors, rear view video camera and/or some type of reverse backup sensors. Furthermore, safer backing up is done when the driver turns completely around and looks out of the rear window of the car, rather than relying on mirrors. This provides a wider field of vision and better control of the vehicle.

Collision prevention

Although many crashes are caused by behavior that is difficult to alter, by mechanical failure, or by road conditions, some technical solutions would automatically detect how close the driver is to the car in front and automatically adjust the car's acceleration to prevent the car from getting closer than the distance in which it can safely stop.

• Sobriety detectors: These locks prevent the ignition key from working if the driver breathes into one and is shown to have consumed alcohol.
• Drifting monitors: These devices monitor how close a vehicle is travelling to lane markers and, if it starts to drift toward or over the markers without the turn signal being activated, sounds an alarm.

Reasons suggested for young and inexperienced drivers being more likely to be in an accident include inexperience combined with over-confidence, peer pressure, a desire to show off, and even neurological development arguments. In addition most serious collisions occur at night and when the car has multiple occupants. This has led to the following proposals:

• A "curfew" imposed on young drivers to prevent them driving at night.
• Requiring an experienced supervisor to chaperone the less experienced driver.
• Forbidding the carrying of passengers.
• Zero alcohol tolerance.
• Compulsory advanced driving courses.
• Vehicle restrictions (eg. 'high performance' vehicles).
• Requiring a sign placed on the back of the vehicle to notify other drivers of a less-experienced individual in the driver's seat.

Some countries or states have already implemented some of these ideas. This increased risk for the young is known to the insurance companies, and premiums sometimes reflect that; however, very high premiums for young drivers do not seem to have had a significant impact on the crash statistics, suggesting that these drivers simply accept the high premiums as part of the "on road" costs of mobility or that age is not a factor in driver recklessness/skill.

A long fall stopped by an early guardrail, ca. 1920

Guardrails, median barriers, or other physical objects can help prevent accidents or minimize damage.

See also

• Unsafe at Any Speed
• Defensive driving
• Crash test
• Crash test dummy
• Driver visibility (List of visibility in cars)
• Vehicle extrication
• Road safety
• Transportation safety in the United States
• Pedestrian safety through vehicle design
• Roadside memorial
• List of road accidents
• In case of emergency (The "ICE" program)
• Tram accident
• Vehicle explosion
• Vehicular accident reconstruction
• Fatal Accident Reconstruction Team
• Totaled

External links

• Early Auto Accidents A Fascinating Collection of Photos of Auto Accidents from the 1920's to 1950's
• Car Crashes Different crashes caught on tape.
• U.S. DOT Fatality Analysis Reporting System FARS
• Frontal and Side car crash video in slow motion
• Car Accident Photos. Thousands of accident images and stories arranged in different galleries
• The Quiet Horror, a critical column by Doug Damerst
• Hints, Tips and Awareness of the dangers of inexperienced driving