An automobile is a wheeled vehicle that carries its own motor. Different types of automobiles include cars, buses, trucks, jeeps, and vans, with cars being the most popular. The term is derived from Greek 'autos' (self) and Latin 'movére' (move), referring to the fact that it 'moves by itself'. Earlier terms for automobile include 'horseless carriage' and 'motor car'. An automobile has seats for the driver and, almost without exception, one or more passengers. It is the main source of transportation across the world.

As of 2005 there are 500 million cars worldwide (0.07 per capita), of which 220 million are located in the United States (0.75 per capita).

The automobile was invented by Carl Benz in Mannheim Germany in 1886.

In almost every nation, laws have been enacted governing the operation of motor vehicles. Most of this legislation, including limits on allowable speed and other rules of the road, are designed to ensure the smooth flow of traffic and simultaneously protect the safety of vehicle occupants, cyclists, and pedestrians.

In 1965, in the U.S. state of California, state legislation was introduced to regulate exhaust emissions, the first such legislation in the world. Answering this new interest in environmental and public safety issues, the Department of Transportation (DOT) and the Environmental Protection Agency (EPA) both introduced legislation in 1968 which substantially altered the course of automotive development. Since the US market was the largest in the world (and California the largest market in the US), manufacturers worldwide were forced to adapt. For the first time, safety devices were mandatory, as were controls on harmful emissions. Prior to this legislation, even seat belts were considered extra-cost options by many manufacturers. Other countries followed by introducing their own safety and environmental legislation. In time, meeting regulations became the main challenge for the engineers designing new cars. In the decade from 1975 to 1985, the world's manufacturers struggled to meet the new regulations, some producing substandard cars with reduced reliability as a result. However, by the end of this period, everyone had learned how to handle the newly regulated environment. The manufacturers discovered that safety and environmentalism sold cars, and some began introducing environmental and safety advances on their own initiative.

The automobile was hailed as an environmental improvement over horses when it was first introduced. Before its introduction, in New York City, over 10,000 tons of manure had to be removed from the streets daily.

Among the first environmental advances are the so-called alternative fuels for the internal combustion engine, which have been around for many years. Early in automotive history, before gasoline was widely available at corner pumps, cars ran on many fuels, including kerosene (paraffin) and coal gas. Alcohol fuels were used in racing cars before and just after World War II. Today, methanol and ethanol are used as petrol extenders in some countries, notably in Australia and the United States. In countries with warmer climates, such as Brazil, alcohol derived from sugar cane is often used as a substitute fuel.

In many countries, plentiful supplies of natural gas have seen methane sold as compressed natural gas (CNG) and propane sold as liquified petroleum gas (LPG) alongside petrol and diesel fuels since the 1970s. While a standard automotive engine will run on these fuels with very low exhaust emissions, there are some performance differences, notably a loss of power due to the lower energy content of the alternative fuels. The need to equip filling stations and vehicles with pressurized vessels to hold these gaseous fuels and more stringent safety inspections, means that they are only economical when used for a long distance, or if there are installation incentives. They are most economical where petrol has high taxes and the alternative fuels do not.

With heavy taxes on fuel, particularly in Europe and tightening environmental laws, particularly in California, and the possibility of further restrictions on greenhouse gas emissions, work on alternative power systems for vehicles continues.

Diesel-powered cars can run with little or no modification on 100% pure biodiesel, a fuel that can be made from vegetable oils. Many cars that currently use gasoline can run on ethanol, a fuel made from plant sugars. Most cars that are designed to run on gasoline are capable of running with 15% ethanol mixed in, and with a small amout of redesign, gasoline-powered vehicles can run on ethanol concentrations as high as 85%. All petrol fueled cars can run on LPG. There has been some concern that the ethanol-gasoline mixtures prematurely wear down seals and gaskets. Further, the use of higher levels of alcohol require that the automobile carry/use twice as much. Therefore, if your vehicle is capable of 300 miles on a 15-gallon tank, the efficiency is reduced to approximately 150 miles. Of course, certain measures are available to increase this efficiency, such as different camshaft configurations, altering the timing/spark output of the ignition, or simply, using a larger fuel tank.

In the United States, alcohol fuel was produced in corn-alcohol stills until Prohibition criminalized the production of alcohol in 1919. Brazil is the only country which produces ethanol-running cars, since the late 1970s.

Attempts at building viable battery-powered electric vehicles continued throughout the 1990s (notably General Motors with the EV1), but cost, speed and inadequate driving range made them uneconomical. Battery powered cars have used lead-acid batteries which are greatly damaged in their recharge capacity if discharged beyond 75% on a regular basis and NiMH batteries.

Current research and development is centered on "hybrid" vehicles that use both electric power and internal combustion. The first hybrid vehicle available for sale in the USA was the Honda Insight. As of 2005, The car is still in production and achieves around 60 mpg.

Other R&D efforts in alternative forms of power focus on developing fuel cells, alternative forms of combustion such as GDI and HCCI, and even the stored energy of compressed air (see Air Engine).

Automobiles were a significant improvement in safety on a per passenger mile basis, over the horse based travel that they replaced. Millions have been able to reach medical care much more quickly when transported by ambulance.

Accidents seem as old as automobile vehicles themselves. Joseph Cugnot crashed his steam-powered "Fardier" against a wall in 1770. The first recorded automobile fatality was Bridget Driscoll on August 17, 1896 in London and the first in the United States was Henry Bliss on September 13, 1899 in New York City.

Worldwide, every year more than a million people are killed and about 50 million people are wounded in collisions (according to WHO estimates). Cars also cause innumerable injuries and deaths among millions of animals (see roadkill). Major factors in accidents include the use of alcohol or other drugs, inattentiveness, the use of handheld mobile phones, tiredness, road hazards such as snow, potholes, and animals, and recklessness. Special safety features have been built into cars for years, some for the safety of car's occupants only, some for the safety of others.

Cars have two basic safety problems: They have human drivers who make mistakes, and the wheels lose traction near a half gravity of deceleration. Automated control has been seriously proposed and successfully prototyped. Shoulder-belted passengers could tolerate a 32G emergency stop (reducing the safe intervehicle gap 64-fold) if high-speed roads incorporated a steel rail for emergency braking. Both safety modifications of the roadway are thought to be too expensive by most funding authorities, although these modifications could dramatically increase the number of vehicles that could safely use a high-speed highway.

Early safety research focused on increasing the reliability of brakes and reducing the flammability of fuel systems. For example, modern engine compartments are open at the bottom so that fuel vapors, which are heavier than air, vent to the open air. Brakes are hydraulic so that failures are slow leaks, rather than abrupt cable breaks. Systematic research on crash safety started in 1958 at Ford Motor Company. Since then, most research has focused on absorbing external crash energy with crushable panels and reducing the motion of human bodies in the passenger compartment.

There are standard tests for safety in new automobiles, like the EuroNCAP and the US NCAP tests. There are also tests run by organizations such as IIHS and backed by the insurance industry.

Despite technological advances, there is still significant loss of life from car accidents: About 40,000 people die every year in the US, with similar trends in Europe. This figure increases annually in step with rising population and increasing travel, but the rate per capita and per mile travelled decreases steadily. The death toll is expected to nearly double worldwide by 2020. A much higher number of accidents result in injury or permanent disability.

There will always be a strong demand for the door-to-door, on-demand service but there are likely to be radical changes in the cars of the future.

• Effects of the automobile on societies
• List of automobile manufacturers
• List of recent automobile models by type
• U.S. Automobile Production Figures
• Car dealership
• Car handling
• Car safety
• Unsafe at Any Speed by Ralph Nader
• Crash test dummy
• Car washing techniques
• List of automotive superlatives, Lists of automobiles for a structured list.
• List of automotive packages (cosmetic and functional features sold as a group)
• Road traffic accident

• engine
  • carburetor or fuel injection
  • fuel pump
  • engine configuration: Wankel or reciprocating (V, inline, flat).
  • engine management systems
  • exhaust system
  • ignition system
  • self starter
  • emissions control devices
  • turbochargers and superchargers
  • front engine
  • rear engine
  • mid engine

• Ancillary power - mechanical, electrical, hydraulic, vacuum, air

• drivetrain
  • transmission (gearbox)
    • manual transmission
    • semi-automatic transmission
    • fully-automatic transmission
  • Layout
    • FF layout
    • FR layout
    • MR layout
    • RR layout
  • Drive Wheels
    • 2 wheel drive
    • 4 wheel drive
    • Front wheel drive
    • Rear wheel drive
    • All wheel drive
  • differential
    • limited slip differential
  • axle
  • Live axle

• brakes
  • disc brakes
  • drum brakes
  • anti-lock braking systems (ABS)

• wheels and tires
  • custom wheels

• steering
  • rack and pinion
  • Ackermann steering geometry
  • Caster angle
  • Camber angle
  • Kingpin

• suspension
  • MacPherson strut
  • wishbone
  • double wishbone
  • multi-link
  • torsion beam
  • semi-trailing arm
  • axle

• body
  • crumple zones
  • monocoque (or unibody) construction
  • suicide doors
  • spoiler

• interior equipment
  • passive safety
    • seat belts
    • airbags
    • child safety locks
  • dashboard
  • shifter for selecting gear ratios
  • ancillary equipment such as stereos, air conditioning, cruise control, car phones, positioning systems, cup holders, etc.

• exterior equipment
  • windows
    • Power window
    • windshield
    • Daytime running lamps

• Department of Motor Vehicles
• A brief history of the automotive form
• Autoweek.com
• Auto Insider
• Edmunds.com
• Kelley Blue Book
• Insurance Institute for Highway Safety
• NHTSA.gov
• Alternative Fuel Vehicle Training
• Car Images and Info
• NetCarShow.com - Archive of car pictures

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