Car Accidents

What is a Car accident.

Car accidents are unintentional damaging events involving automobiles. Car accidents can damage one or more autos, people, or structures. Car accidents—also called traffic accidents, auto accidents, road accidents, road traffic accidents (RTA in many police forces' terminology) and motor vehicle accidents—cause thousands of deaths and hundreds of thousands of disabilities each year.

Worldwide, car accidents kill an estimated one million people each year (a 2002 statistic).

Types of accidents

Car accidents fall into several major categories (whose names are self-explanatory):

- Rear-end collisions

- Rollovers

- Head-on collisions

- Single-car accidents

- Pile-ups

- Railroad crossing accidents

Rear-end collisions

A Rear-end collision (often called simply rear-end) is a traffic accident where a vehicle (usually an automobile or a truck) impacts the vehicle in front of it, so called because it thus hits its rear.

Typical scenarios for rear-ends are i) a sudden deceleration by the first car (for example, to avoid someone crossing the street), ii) the following car that does not have the time to brake and impacts the first and iii) at a road junction the following car accelerates more rapidly than the leading.

In rear-ends, mechanical damage is equally shared by the two vehicles if they have identical plasticity and mass. Injuries to the occupants are usually much worse for the impacted vehicle, because occupants of the following vehicle often anticipate the imminent impact and take automatic measures.

As a rule of thumb, impacting into another car is equivalent to impacting into a rigid surface (like a wall) at half of the speed. This means that rear-ending a still car while going at 30 mph is equivalent, in terms of forces, to impacting a wall at 15 mph. The same is true for the impacted vehicle.

A typical medical consequence of rear-ends, even in case of collisions at moderate speed, is whiplash.

For purposes of insurance and policing, the driver of the car that rear-ends the other car is almost always considered to be at fault.

Rollovers

Rollover is a type of car accident, where a vehicle turns over on its side or roof. This happens when the centre of mass ends up outside of the vehicle area of contact with the ground defined by its wheels.

The main cause for rolling over is turning too sharply while moving too fast. The force of inertia (acting in the direction opposite to the one it is turning) is combined with the force of gravity (acting downwards). When the combined force as applied to the centre of vehicle's mass falls outside of the rectangle formed by the wheels, the vehicle starts to turn over. A skilled driver may stop the fall by stopping the turn. It is possible to drive the car then on two wheels for some time.

All cars are susceptible to rollovers to various extents. Generally, the higher the centre of mass is located, the higher the vehicle is and the faster it goes, the more likely it is to roll over. SUVs are particularly notorious for rolling over. Hummer jeeps, on the other hand, are nearly invulnerable to this type of accident. According to anecdotal evidence, however, it can be rolled in very specific curcumstances and this was done on purpose twice in Israeli army. A driver needs to move backwards very fast and then do a sharp turn, and immediately slam the brakes to block the wheels.

Trucks can often roll over when doing sharp turns and trains can roll over after derailing.

Some four wheel drive pickup trucks have reduced steering capacity to prevent rollover. This creates problems with parking and negotiating very sharp curves.

A vehicle may roll over for other reasons, for example when hitting a large obstacle with one of its wheels, when manoeuvring over uneven terrain, etc.

After the rollover the vehicle may end up lying on the side or on the roof, often blocking the doors and complicating the escape for the passengers. Large passenger vehicles such as buses, trams and trolleybuses that have doors on one side only usually have special windows with handles to pull to use the window as an emergency exit or glaziers fixed near the windows for cutting the glass and making an improvised exit in case of a rollover. Some have emergency exits in their roofs.

Head-on collisions

A head-on collision is one where the front ends of the ships, trains, planes or vehicles hit each other, as opposed to a side-collision or rear-end collision.

Road transport

In the context of freeways, such collisions are particularly difficult to avoid, since freeways were designed to facilitate high-speed travel. The resulting car accidents are often fatal.

Some U.S. states have installed special signage at freeway off-ramps to discourage drivers from going the wrong way.

Single-car accidents

Worldwide, car accidents kill an estimated one million people each year (a 2002 statistic).

Pile-ups

A pile-up is a traffic accident involving many vehicles. Generally occurring on highways they are one of the deadliest form of traffic accidents.

Pile-ups generally occur in low-visibility conditions, like rain or fog. In such conditions drivers on highways often drive closer together than they should. If one car develops a problem, those behind it cannot stop in time, hitting it. As cars are forced into other lanes and oncoming traffic more vehicles become involved. The most disastrous pile-ups have involved more than a hundred vehicles.

They are particularly deadly as the solid mass of crumpled vehicles makes escape difficult. A fire in one part of the accident can quickly spread to spilled fuel and cover the entire crash area. Vehicles in a pile up are often hit multiple times, increasing risk of injury to the passenger. Moreover cars are often spun during an accident and are subsequently hit from the side, increasing risk of injury or death. Some vehicle occupants choose to get out of their vehicles during a pile up, making them vulnerable to oncoming vehicles. Pile-ups can also overburden local firefighting, ambulance, and police services making quick rescues more difficult.

The large scale of these accidents can close important routes for several days. The destruction and intense heat of fires can also damage roadways, particularly by melting and burning the asphalt. A pileup inside a tunnel is by far the worst, as there is little means for escape in older ones, and the unvented heat may even cause the concrete lining to come apart.

Determining the cause of such accidents is also difficult for investigators and it is often impossible to tell if negligence caused the crash.

Railroad crossing accidents

The term level crossing (also called: railroad crossing or grade crossing) is a crossing on one level (or "at grade") - without recourse to a bridge or tunnel - used to describe the crossing of a railway line by a road, path, or other railroad.

It also applies when a light rail line with separate right-of-way (or a reserved track tramway) crosses a road; the term "metro" usually means by definition that there are no level crossings (i.e. that the system is grade-separated).

About Rail Crossings

In the United States, and in countries following US practices, a train must have a bright headlight, and a whistle or horn must be sounded as the train approaches the crossing. Some American cities, citing noise pollution abatement, have passed laws prohibiting the sounding of bells and whistles, however their ability to enforce such rules is debatable. In December of 2003, The US Federal Railroad Administration published regulations that would create areas where train horns could be silenced, provided that certain safety measures were put in place. More information can be found at the FRA website at and following the page link under 'Train horn rule.' The regulations were scheduled to go into effect in December 2004.

All crossings in the United States are required to be marked by at least a crossbuck. Most crossings that intersect rural roads have this setup. As traffic on the road crossing or the rail crossing increases, safety features are ramped up accordingly. More densely populated crossings have alternately flashing red lights to warn motorists, and a bell to warn pedestrians. Additional safety is attained through gates that block motorists approach to the tracks when activated. Increasingly, crossings are being fitted with so-called four-quadrant gates, with a gate mechanism on either side of the tracks for each direction of automotive traffic. The exit gates blocking the road leading away from the tracks in this application are equipped with a delay, and begin their descent to their horizontal position several seconds after the entrance gates do, so as to avoid trapping highway vehicles on the crossing. Four-quadrant gates prevent vehicles from driving around lowered gates to try to beat a train.

A track that will run high-speed trains in excess of 120 mph (193 km/h) is being tested in Illinois between Chicago and Saint Louis. Here, due to the high speed of the trains, gates that totally prevent road traffic from reaching the tracks are mandatory on all level crossings, and steel mesh nets are being tested on the busier crossings to further prevent collisions.

Safety

The original design for a level crossing consisted of a flagman in a nearby booth who would on the approach of a train, race out with a stop sign or red lantern and (attempt to) stop all traffic and clear the tracks. Manual or electrical closable gates which barricaded the roadway were later introduced. The gates were intended to be a complete barrier against intrusion of any road traffic onto the railway. With the appearance of motor vehicles, this barrier became less and less effective, and therefore pointless. Rising wage levels made the continuance of the older style crossing financially impossible. The decision was reached to substitute comparatively flimsy, but highly visible, unmanned barriers operated by the approach of a train but which are not linked with the railway signalling system, and to rely on road users following the associated warning signals to stop. In some cases the barrier only closes across the approach lane, and the other lane has no barrier. This is intended to allow slow vehicles to escape from a crossing when the barriers are dropping. It unfortunately allows impatient drivers to zig-zag round the half barriers to avoid any delay, and provides a potential collision risk.

In many countries, on less important roads and railway lines, level crossings are often "open" or "uncontrolled" but these have warning lights or bells to warn of approaching trains. Ungated crossings represent a safety issue; many accidents have occurred due to failure to notice or obey the warning. Railways in the United States are adding reflectors to the side of each train car to help prevent accidents at level crossings. In some countries, such as Ireland, instead of an open crossing there may be manually operated gates, which the motorist must open and close. These too have significant risks, as they are unsafe to use without possessing a knowledge of the train timetable: motorists may be instructed to telephone the railway signaller, but may not always do so.

The consensus in contemporary railway design is to avoid the use of level crossings. The director of rail safety at the UK Railway Inspectorate commented in 2004 that "the use of level crossings contributes the greatest potential for catastrophic risk on the railways." Eighteen people were killed in the UK on level crossings in the 2003-4 period. Bridges and tunnels are favoured, and there is a commitment on the part of UK rail authorities not to build new level crossings, and to reduce the number of existing level crossings from the present 8,200. The cost of making significant reductions, other than by simply closing the crossings, would be substantial, and a number of commentators argue that the money could be better spent. Some 6,500 of the 8,200 crossings are user-worked crossings or footpaths, with very low usage.

In November 2004 there were two major accidents on UK level crossings: one involved a car driver suspected of being a suicide, who caused the death of seven people (see Ufton Nervet rail crash); another involving a train carrying 50 school children resulted in no fatalities but a number of injuries. These incidents have increased efforts to review the placing of level crossings and to eliminate them where this is practicable. In the UK it has also been suggested that cameras similar to the type used to detect drivers who run traffic lights be deployed at level crossings, and that penalties for ignoring signals should be much more severe.

Third rail systems may also have level crossings: there is a gap in the third rail over the level crossing, but in spite of that the power supply is not interrupted since trains have current collectors in the front and rear cars; however, care must be taken that a current or voltage gap is not created between the two ends.

At railway stations a pedestrian level crossing is sometimes provided to allow passengers to reach other platforms in the absence of an underpass or bridge.

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Causes of Car accidents.

Many factors result in car accidents, and sometimes multiple causes contribute to a single accident. Factors include the following:

* Driver distraction, including fiddling with technical devices as noted previously, talking with passengers, eating or grooming in the car, dealing with children or pets in the back seat, or attempting to retrieve dropped items.

* Driver impairment by tiredness, illness, alcohol or other drugs, both legal and illegal. MADD (Mothers Against Drunk Driving) is an organization made up of the families of the dead who were killed in car accidents caused by drunk drivers.

* Mechanical failure, including flat tires or tires blowing out, brake failure, axle failure, steering mechanism failure.

* Road conditions, including foreign obstacles or substances on the road surface; rain, ice, or snow making the roads slick; road damage including pot holes.

* Speed exceeding safe conditions, such as the speed for which the road was designed, the road condition, the weather, the speed of surrounding motorists, and so on.

* Road design and layout. Some roads are notorious for being accident "black spots" for a whole variety of reasons, many subtle and not necessarily immediately obvious. These include alignment, visibility, camber and surface conditions, road markings, etc. Finding out the causes for a repeated series of accidents on the same stretch of road is becoming a science in itself.

Many authorities emphasise speed as an inherent cause of accidents in itself, though most experts agree that speed alone is rarely a prime cause of accidents, though naturally a mis-application of speed can be a contributing factor, and higher speed in an accident resulting from whatever cause is more likely to have serious consequences. Critics of the "speed kills" mentality claim that this approach ignores the complex factors that are involved in accidents, and argue that it amounts to little more than a simplistic "quick fix" or political solution that does nothing to address the true causes of accidents. Proponents state that going slower at least can do no harm, and that physics is on their side, since the outcome of an accident largely depends on the energy dissipated in a crash, and that energy rises with the square of velocity, according to the equation E = ½ ·m·v², where E is the kinetic energy, m is the mass, and v is the velocity. The first person who died in a petrol engined car accident, Bridget Driscoll, was killed by a car driving only 4 miles/h (6.5 km/h).

Attempts to force car manufacturers to limit the top speed of vehicles has so far been resisted by both the manufacturers and governments themselves. Partly this is because the car manufacturers have substantial political lobbying power and speed and performance are powerful marketing tools, and partly because it is easy to show that such measures are unlikely to have a significant effect on the road toll, and might then force governments to seriously address the more complex causes of accidents. A recent proposal in Australia for car manufacturers to fit speedometers which are blank above 130 km/h (whatever the actual top speed of the vehicle) has proved extremely controversial, and legally unworkable, according to most commentators.

Rubbernecking

Rubbernecking is where drivers slow down to look at accidents or anything out of the ordinary on the highway. Events ranging from gruesome car accidents to a police car stopped on the shoulder can cause traffic jams on both sides of the road, even if the roadway has been cleared.

Although caution is advised when there is unexpected activity on the side of a road, a car with a flat tire on the side of a highway often causes as much slow down as a real accident would due to rubbernecking. The slowdown in traffic persists even after the accident scene has been cleared if traffic is dense. Traffic experts call this phenomenon a phantom accident. Often this behavior causes additional and sometimes more serious accidents among the rubberneckers.

Legal issues with Car accidents.

Car accidents often carry legal consequences in proportion to the severity of the accident. 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 the crime of hit and run.

Parties involved in an accident 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 intoxicated or otherwise impaired at the time the accident occurred. Charges might include driving under the influence of alcohol, assault with a deadly weapon, manslaughter, or murder; penalties range from fines to jail time to prison time to death.

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 most usually decide solely the factual questions of who is at fault, and how much they (or their insurer) must pay out in damages to the injured plaintiff.

Another element of civil liability involves the administrative fines or license suspension/revocation that may be imposed by a civil authority 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.

Car accident prevention.

Although many accidents are caused by behavior that is difficult to alter, by mechanical failure, or by road conditions, some technical solutions are becoming more widely available to prevent accidents:

* Proximity monitors: These would automatically detect how close you were traveling to the car in front of you and automatically adjust your car's acceleration to prevent you from getting closer than you can safely stop at your current speed.

* 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 traveling to lane markers and, if it starts to drift toward or over the markers without the turn signal being activated, sounds an alarm.

In most developed countries, young (under 25 years old) male drivers have been shown to be by far the most likely to be involved in a car accident, and this has become an area of focus in recent times. Reasons suggested for this prevalence include inexperience combined with over-confidence, peer pressure, showing off, and even neurological development arguments. In addition most serious accidents occur at night and when the car has multiple occupants. This has led to some discussion of 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.

* 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, but so far no consensus to a total solution has been reached. It should be noted that this prevalence has long been noted by insurance companies, and premiums reflect that; however, very high premiums for young male drivers does not seem to have had a significant impact on the accident statistics, suggesting that these drivers simply accept the high premiums as part of the "on road" costs of mobility.

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