There are an estimated 6 million road accidents in the US each year. About half of this number - 3 million people - are injured in these accidents. The injuries may range from minor scrapes to permanent disabilities. The number of mortal casualties in car crashes each year is estimated to be well over 40,000.

Car crashes are caused due to a number of reasons. Disobedience of traffic safety rules are the prime cause. Jumping signals, reckless driving and speeding are among the major causes of car crashes. Car crashes due to drunken and drugged driving are becoming an issue of great concern throughout the world. Use of mobile phones while driving diverts the attention of the driver and may cause an accident. Laws have been passed in several states forbidding drinking and the use of cell phones during driving.

Car crashes have been categorized according to the part that collides. They are head-on collisions, rollovers, side collisions, rear end collisions, level crossing collisions, etc. Head-on collisions are the most lethal and are almost always fatal to the people in the front seats. Head-on collisions lead to a shattering of the front glass which may cause more serious injuries. A rollover or ""turning turtle"" occurs when a car at a high speed collides with something. Such accidents may cause permanent paralysis of the victims, if not death.

The seriousness of car accidents has prompted vehicle manufacturers to devise and use new safety measures in their cars. Proximity meters are used in some recent cars. These meters can detect the safe distance from a vehicle ahead of it and can automatically change the acceleration of the vehicle to maintain that distance. Another invention is the built-in breathalyzer or the sobriety meter which locks the car if it detects over 10% of alcohol in the breath of the driver. There are other simple measures such as automatically inflating air cushions and seatbelts.

There is always some legislation involved with a car crash. The severity of the legislation depends on the impact of the crash. People involved in a car crash are supposed to stall their vehicle and inform the police immediately. The party responsible for the crash may have to compensate the injured victim. Suits are filed if the case is too serious; otherwise a roadside settlement may be done with the traffic policeman as the intermediary.

Several measures are being adopted to prevent car crashes. Efforts are on to make advanced driving classes compulsory. Hoardings are put up at prominent places and gruesome car accident clips are shown on television to make people wary of rash driving. Severe penalties are imposed on people indulging in driving when drunk or under the influence of drugs. The National Highway Traffic Safety Administration is constantly modifying these and other rules to reduce the number of car crashes in the country.