Impaired driving is operating a vehicle while under the influence of alcohol, legal or illegal drugs.
Alcohol has a significant effect on driving skills due to its depressant effects. While under the influence of alcohol, drivers can misjudge their capabilities and experience the following:
- Decreased reaction time due to slower reflexes
- Feelings of drowsiness
- Poor coordination affecting the mechanics of driving (steering, working, braking, etc.)
- Inattention to driving tasks
- Decreased rational decision making
- Depressed eye movement and perception affecting night vision and color perception
- Inability to judge car’s potion on the road, road signs and location of other vehicles
(Taibbi, R. How Alcohol Affects You. Current Health, Vol. 2, p. 16-19 (1994).)
Drug-impaired driving refers to driving after taking any prescription or over the counter drug, or illegal substances. Like alcohol, drugs can decrease your reaction time, affect your coordination, make you fall asleep at the wheel or lead to inattention while driving.
In 2013, NHTSA’s Fatality Analysis Reporting System (FARS) reported that drugs were present in 40 percent of the fatally-injured drivers with a known test result, almost the same level as alcohol (FARS, 2015). In particular, marijuana use is increasing. As of August 2015, marijuana may be used for medical purposes in 23 states and the District of Columbia (NCSL, 2015a). Recreational use is allowed in Alaska, Colorado, Hawaii, Oregon, Washington and the District of Columbia and 16 other states have decriminalized possession of small amounts of marijuana (NCSL, 2015b).
Fatigue-impaired driving can be just as dangerous as alcohol or drug-impaired driving.
Driving when you’re too tired can have the following affects:
- Impair reaction time, judgment, and vision
- Create problems with information processing and short-term memory
- Decrease performance, vigilance, and motivation
- Increase moodiness and aggressive behaviors
Just like drugs or alcohol, sleepiness slows reaction time, decreases awareness, and impairs judgment. Just like alcohol, sleepiness can be fatal when driving. Groups who are especially at risk for fatigue-impaired driving are drivers under 25 years of age, shift workers, commercial truck drivers and business travelers. For more information visit drowsydriving.org. (National Sleep Foundation)