Traffic collision in the context of Tailgating

Emergency services and rescue services are organizations that ensure public safety, security, and health by addressing and resolving different emergencies. Some of these agencies exist solely for addressing certain types of emergencies, while others deal with ad hoc emergencies as part of their normal responsibilities. Many of these agencies engage in community awareness and prevention programs to help the public avoid, detect, and report emergencies effectively. Emergency services are often considered first responders, and typically have dedicated emergency vehicles.

Emergency services have one or more dedicated emergency telephone numbers reserved for critical emergency calls. In many countries, one number is used for all of the emergency services (e.g. 911 in many parts of the Americas, 999 in the United Kingdom, 112 in continental Europe, 000 in Australia). In some countries, each emergency service has its own emergency number (e.g. 110 for police, 118 for coast guard, 119 for fire and medical in Japan; 110 for police, 119 for fire, 120 for medical in China). Calls made to emergency services to report emergencies are called calls for service.

Vehicle insurance (also known as car insurance, motor insurance, or auto insurance) is insurance for cars, trucks, motorcycles, and other road vehicles. Its primary use is to provide financial protection against physical damage or bodily injury resulting from traffic collisions and against liability that could also arise from incidents in a vehicle. Vehicle insurance may additionally offer financial protection against theft of the vehicle, and against damage to the vehicle sustained from events other than traffic collisions, such as vandalism, weather or natural disasters, and damage sustained by colliding with stationary objects. The specific terms of vehicle insurance vary with legal regulations in each region.

Post-traumatic stress disorder (PTSD) is a mental disorder that develops from experiencing a traumatic event, such as sexual assault, domestic violence, child abuse, warfare and its associated traumas, natural disaster, bereavement, traffic collision, or other threats on a person's life or well-being. Symptoms may include disturbing thoughts, feelings, or dreams related to the events, mental or physical distress to trauma-related cues, attempts to avoid trauma-related cues, alterations in the way a person thinks and feels, and an increase in the fight-or-flight response. These symptoms last for more than a month after the event and can include triggers such as misophonia. Young children are less likely to show distress, but instead may express their memories through play.

Most people who experience traumatic events do not develop PTSD. People who experience interpersonal violence such as rape, other sexual assaults, being kidnapped, stalking, physical abuse by an intimate partner, and childhood abuse are more likely to develop PTSD than those who experience non-assault based trauma, such as accidents and natural disasters. In the United States, about 3.5% of adults have PTSD in a given year, and 9% of people develop it at some point in their lives. In much of the rest of the world, rates during a given year are between 0.5% and 1%. Higher rates may occur in regions of armed conflict. It is more common in women than men.

An injury is any physiological damage to living tissue caused by immediate physical stress. Injuries to humans can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or overexertion. Injuries can occur in any part of the body, and different symptoms are associated with different injuries.

Treatment of a major injury is typically carried out by a health professional and varies greatly depending on the nature of the injury. Traffic collisions are the most common cause of accidental injury and injury-related death among humans. Injuries are distinct from chronic conditions, psychological trauma, infections, or medical procedures, though injury can be a contributing factor to any of these.

An airbag or supplemental inflatable restraint is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a collision and then deflate afterwards. It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. The purpose of the airbag is to provide a vehicle occupant with soft cushioning and restraint during a collision. It can reduce injuries between the flailing occupant and the vehicle's interior.

The airbag provides an energy-absorbing surface between the vehicle's occupants and a steering wheel, instrument panel, body pillar, headliner, and windshield. Modern vehicles may contain up to ten airbag modules in various configurations, including driver, passenger, side-curtain, seat-mounted, door-mounted, B- and C-pillar mounted side-impact, knee bolster, inflatable seat belt, and pedestrian airbag modules.

Automotive safety is the study and practice of automotive design, construction, equipment and regulation to minimize the occurrence and consequences of traffic collisions involving motor vehicles. Road traffic safety more broadly includes roadway design.

One of the first formal academic studies into improving motor vehicle safety was by Cornell Aeronautical Laboratory of Buffalo, New York. The main conclusion of their extensive report is the crucial importance of seat belts and padded dashboards. However, the primary vector of traffic-related deaths and injuries is the disproportionate mass and velocity of an automobile compared to that of the predominant victim, the pedestrian.

Implied consent is consent which is not expressly granted by a person, but rather implicitly granted by a person's actions and the facts and circumstances of a particular situation (or in some cases, by a person's silence or inaction). For example, if a person is unconscious as a result of injuries sustained during a traffic collision, medical treatment may be provided to that person, despite the unconscious person being unable to expressly grant consent for that treatment.

Roadkill is a wild animal that has been killed by collision with motor vehicles. Wildlife-vehicle collisions (WVC) have increasingly been the topic of academic research to understand the causes, and how they can be mitigated.

In law and insurance, a proximate cause is an event sufficiently related to an injury that the courts deem the event to be the cause of that injury. There are two types of causation in the law: cause-in-fact, and proximate (or legal) cause. Cause-in-fact is determined by the "but for" test: But for the action, the result would not have happened. (For example, but for running the red light, the collision would not have occurred.) The action is a necessary condition, but may not be a sufficient condition, for the resulting injury. A few circumstances exist where the but-for test is ineffective (see But-for test below). Since but-for causation is very easy to show (but for stopping to tie your shoe, you would not have missed the train and would not have been mugged), a second test is used to determine if an action is close enough to a harm in a "chain of events" to be legally valid. This test is called proximate cause. Proximate cause is a key principle of insurance and is concerned with how the loss or damage actually occurred. There are several competing theories of proximate cause (see Other factors). For an act to be deemed to cause a harm, both tests must be met; proximate cause is a legal limitation on cause-in-fact.

The formal Latin term for "but for" (cause-in-fact) causation, is sine qua non causation.

A first responder is a person with specialized training who is among the first to arrive and provide assistance or incident resolution at the scene of an emergency. First responders typically include:

• law enforcement officers (commonly known as police officers),
• emergency medical services members (such as EMTs or paramedics), and
• fire service members (such as firefighters, search and rescue members, technical/heavy rescue members, etc.)

In some jurisdictions, emergency department personnel, such as doctors and nurses, are also required to respond to disasters and critical situations, designating them first responders; in other jurisdictions, military and security forces may also be authorized to act as first responders.

An accidental death is an unnatural death that is caused by an accident, such as a slip and fall, traffic collision, or accidental poisoning. Accidental deaths are distinguished from death by natural causes, disease, and from intentional homicides and suicide. An accidental death can still be considered a homicide or suicide if a person was the unintentional cause.

For criminal purposes, intentional homicides are usually classified as murder. Exceptions such as self-defense vary by jurisdiction, and in some cases, persons accused of murder have asserted as a defense that the deceased was actually the victim of an accidental death, rather than an intentional act. However, a person who is responsible for the accidental death of another through negligence may still be criminally liable for manslaughter, and civilly liable for wrongful death. Accidental death and dismemberment insurance and similar insurance policies pay a benefit in the event of accidental death, With these policies it must be demonstrated that a given death is in fact an accident, rather than an intentional suicide or homicide (which might involve insurance fraud).

The AAA Foundation for Traffic Safety (see also American Automobile Association - AAA) is a non-profit, charitable organization based in Washington, DC, that is dedicated to saving lives through traffic safety research and education. Since its founding in 1947, the AAA Foundation has sponsored over 200 projects related to highway safety, covering topics such as distracted, impaired, and drowsy driving; road rage; graduated driver licensing; driver's education and training; and pedestrian safety. The AAA Foundation research agenda is centered on four priority areas: Driver behavior and performance, emerging technologies, roadway systems and drivers and vulnerable road users.

Research in each of these areas is intended to identify the causes and consequences of motor vehicle crashes, evaluate possible countermeasures and solutions, and offer recommendations for achieving the overarching goal of preventing injuries and fatalities on the nation's highways.

Street racing is an illegal form of motor racing that occurs on a public road. Racing in the streets is considered an ancient hazard, as horse racing occurred on streets for centuries, and street racing in automobiles is likely as old as the automobile itself. Street racing is popular and hazardous, with deaths of bystanders, passengers, and drivers occurring yearly.

Street racing can either be spontaneous or well-planned and coordinated. Well-coordinated races are planned and often have people communicating via two-way radios or citizens' band radio, and using police scanners and GPS units to mark locations where local police are more prevalent. Opponents of street racing claim street races have a lack of safety relative to sanctioned racing events, as well as safety risks arising from traffic collisions resulting in injuries and deaths, legal reprucusions and harm to bystanders. Street racing is distinct from the legal and governed sport of drag racing.

A risk–benefit ratio (or benefit-risk ratio) is the ratio of the risk of an action to its potential benefits. Risk–benefit analysis (or benefit-risk analysis) is analysis that seeks to quantify the risk and benefits and hence their ratio.

Analyzing a risk can be heavily dependent on the human factor. A certain level of risk in our lives is accepted as necessary to achieve certain benefits. For example, driving an automobile is a risk many people take daily, also since it is mitigated by the controlling factor of their perception of their individual ability to manage the risk-creating situation. When individuals are exposed to involuntary risk (a risk over which they have no control), they make risk aversion their primary goal. Under these circumstances, individuals require the probability of risk to be as much as one thousand times smaller than for the same situation under their perceived control (a notable example being the common bias in the perception of risk in flying vs. driving).