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Human And Driver Impairment Factors That Cause Auto Accidents



Auto accidents can be caused by human and driver impairment factors.

What Is Meant by Human Factors?

Human factors are one of the causes of motor vehicle accidents. This category encompasses all of the factors that are related to drivers and other users of the roadways (such as cyclists and pedestrians) that can possibly contribute to a collision. The following are examples of common human factors that cause auto accidents:

  • driver behavior and conduct
  • visual acuity
  • auditory acuity
  • decision-making skills and abilities
  • reaction speed

A popular 1985 published study reported crash data for British and American auto accidents. That study reported that driver error, drunkenness, and other similar human factors contribute in part, if not completely, to almost the entirety of crashes (93 percent of them). Often, drivers are more confident in their abilities than they should be. It should come as no big surprise then that almost all drivers who have experienced an auto accident did not consider themselves to be at fault in causing or contributing to the accident.

What Is Meant by Driver Impairment Factors?

Driver impairment is a descriptor that encompasses all of the factors that might prevent a driver from driving at his or her normal level of skill and competency. For example, some of the more common driver impairments include the following:

  • alcohol
  • drugs (illegal, prescription or over-the-counter)
  • otherwise driving under the influence of a substance
  • physical impairment
  • bad eyesight
  • advanced age
  • sleep deprivation
  • fatigue

Poor eyesight is a common cause of impaired driving. As a result, many state jurisdictions require simple vision screenings or testing when driver's licenses are first obtained and each time they are renewed. Many states restrict driver's licenses for those who need glasses or contact lenses and designate such restrictions on the driver's license card.

For parties with more chronic, long-term, or deteriorating physical conditions or impairments, the jurisdiction may require certain vehicle modifications before a particular driver is permitted to drive. An example of this latter situation occurs with a handicapped driver who may require hand controls or brakes on his or her vehicle instead of standard pedals.

Similarly, for older drivers past a given advanced age in a jurisdiction, drivers may be tested for reaction speeds and vision at each license renewal or more frequent intervals. Behind-the-wheel tests at driver's license renewals or vision tests may be required of these older drivers to ensure their competency.

In the instance of impairment due to drugs, antihistamines, opioids, and muscarinic antagonists are some of the over the counter drugs that typically cause motor skill, coordination, and reaction time problems that may adversely impact a driver's abilities. Illegal drugs and the abuse of prescription drugs are also potential causes of dangerous driver impairment.