Visual and auditory acuity no relation substance intoxication
Human factors
Human factors in vehicle collisions include anything related to drivers and other road users that may contribute to a collision. Examples include driver behavior, visual and auditory acuity, decision-making ability, and reaction speed.
A 1985 report based on British and American crash data found driver error, intoxication, and other human factors contribute wholly or partly to about 93% of crashes. A 2019 report from the U.S. National Highway Traffic Safety Administration found that leading contributing factors for fatal crashes included driving too fast for conditions or in excess of the speed limit, operating under the influence, failure to yield right of way, failure to keep within the proper lane, operating a vehicle in a careless manner, and distracted driving.Drivers distracted by mobile devices had nearly four times greater risk of crashing their cars than those who were not. Research from the Virginia Tech Transportation Institute has found that drivers who are texting while driving are 23 times more likely to be involved in a crash as non-texting drivers. Dialing a phone is the most dangerous distraction, increasing a drivers' chance of crashing by 12 times, followed by reading or writing, which increased the risk by ten times.An RAC survey of British drivers found 78% of drivers thought they were highly skilled at driving, and most thought they were better than other drivers, a result suggesting overconfidence in their abilities. Nearly all drivers who had been in a crash did not believe themselves to be at fault. One survey of drivers reported that they thought the key elements of good driving were:
controlling a car including a good awareness of the car's size and capabilities
reading and reacting to road conditions, weather, road signs, and the environment
alertness, reading and anticipating the behavior of other drivers.Although proficiency in these skills is taught and tested as part of the driving exam, a "good" driver can still be at a high risk of crashing because:Driver impairment
Driver impairment describes factors that prevent the driver from driving at their normal level of skill. Common impairments include:Alcohol
According to the Government of Canada, coroner reports from 2008 suggested almost 40% of fatally injured drivers consumed some quantity of alcohol before the collision.
Physical impairment
Poor eyesight and/or physical impairment, with many jurisdictions setting simple sight tests and/or requiring appropriate vehicle modifications before being allowed to drive.
Youth
Insurance statistics demonstrate a notably higher incidence of collisions and fatalities among drivers aged in their teens or early twenties, with insurance rates reflecting this data. These drivers have the highest incidence of both collisions and fatalities among all driver age groups, a fact that was observed well before the advent of mobile phones.Females in this age group exhibit somewhat lower collision and fatality rates than males but still register well above the median for drivers of all ages. Also within this group, the highest collision incidence rate occurs within the first year of licensed driving. For this reason, many US states have enacted a zero-tolerance policy wherein receiving a moving violation within the first six months to one year of obtaining a license results in automatic license suspension. South Dakota is the only state that allows fourteen-year-olds to obtain drivers' licenses.
Old age
Old age, with some jurisdictions requiring driver retesting for reaction speed and eyesight after a certain age.
Sleep deprivationVarious factors such as fatigue or sleep deprivation might increase the risk, or numbers of hours driving might increase the risk of an incident. 41% of drivers self report having fallen asleep at the wheel.: 41  It is estimated that 15% of fatal crashes involve drowsiness (10% of day time crashes, and 24% of night time crashes). Work factors can increase the risk of drowsy driving such as long or irregular hours or driving at night.
Drug use
Including some prescription drugs, over the counter drugs (notably antihistamines, opioids and muscarinic antagonists), and illegal drugs.
Distraction
Research suggests that the driver's attention is affected by distracting sounds such as conversations and operating a mobile phone while driving. Many jurisdictions now restrict or outlaw the use of some types of phone within the car. Recent research conducted by British scientists suggests that music can also have an effect; classical music is considered to be calming, yet too much could relax the driver to a condition of distraction. On the other hand, hard rock may encourage the driver to step on the acceleration pedal, thus creating a potentially dangerous situation on the road.Cell phone use is an increasingly significant problem on the roads and as the U.S. National Safety Council compiled more than 30 studies postulating that hands-free is not a safer option, because the brain remains distracted by the conversation and cannot focus solely on the task of driving.
no relation