According to a study conducted by the Transportation Research Board of the National Academies (TRB) and published on the National Transportation Library Integrated Search (TRIS) website, most people are aware of the impairment cased by alcohol and its affect on driving. However, fewer people recognize other factors that can impair the ability to drive. For example drugs, sleep deprivation, and distractions each can have serious effects on one's driving ability.
Alcohol
Well known is the fact that the consumption of alcohol can cause impairment. Perhaps less recognized is that fact that impairment rises gradually at a lower level but dramatically at a higher level of blood alcohol concentration BAC. About half of auto fatalities involve drivers with BACs of .16 or higher. Impairment occurs at a lower level, but it is especially important to prevent driving with high BACs. The Best advice is do not drink and drive.
Drugs
The use of medications considered harmless is one of the leading causes sleep-related motor vehicle accidents. Medications such as antihistamines, analgesics, heart medications, certain antibiotics, and minor tranquilizers such as the ones used to treat depression or other psychological conditions can impair driving by causing drowsiness, dizziness, or nausea.
Drugs and driving may be a bigger problem than generally recognized. A New England Journal of Medicine report on drivers without alcohol in their systems who were stopped by police for reckless driving found that 45% had marijuana and 25% had cocaine in their systems. A study by The Insurance Institute for Traffic Safety of interstate tractor-trailer drivers found that 15% of all drivers had marijuana, 12% had non-prescription stimulants, 5% had prescription stimulants, 2% had cocaine, and less than 1% had alcohol in their systems. A National Transportation Safety Board investigation of fatal truck accidents found that stimulants were the most frequently unidentified (15%) drug class among fatally injured truck drivers. Stimulants may be widely used to combat another under-reported killer, driving while sleep-deprived or fatigued.
Sleep Deprivation
According to estimates by the National Sleep Foundation, in the United States 1,500 people die and 71,000 are injured annually because of fatigue-related accidents. Driving when tired is greatly under reported because there is no test for it, as there is for intoxication, no clear way to identify it, and many states do not have a code for it on their vehicle accident reporting forms. The National Highway Traffic Safety Administration (NHTSA) estimates that about 100,000 police-reported crashes annually involve drowsiness/fatigue as a principle cause. About 1,000,000 crashes annually -- one-sixth of all crashes -- are thought to be caused by driver inattention and lapses. Sleep deprivation and fatigue make such lapses of attention more likely to occur. The National Science Foundation found that 62% of all adults surveyed in the US reported driving a car or other vehicle while they were drowsy during the previous year.
Distractions
In addition to avoiding substance impairment, it is important not to become distracted. Such things as using a cell phone, eating, combing your hair, or applying make-up while driving easily cause distraction. Having a passenger in the vehicle can also distract a driver. Make sure children are safely secured are try to lower the amount of time you spend looking at them instead of at the road. Many drivers become complacent while driving and follow road precautions loosely.
