South Dakota driving lesson · Be in Shape to Drive
How alcohol and drugs impair you
A 3-minute lesson from the South Dakota course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Impairment starts with the first drink. Alcohol and other drugs dull exactly the skills driving needs most, such as judgment, vision and reaction time, and new drivers are hit hardest.
Alcohol and other impairing drugs reduce:
Judgment: using stored experience and knowledge to handle new problems quickly
Vision: blur, slower focus, double vision, poor judging of distance, speed and movement
Color distinction
Reaction time: slower processing of information and response
THINK signs: since 1979, one sign stands on the state highway for each person killed in a crash, as a memorial and a reminder about DUI, seatbelts, speeding and distraction.
You took an allergy pill this morning and feel a bit foggy. Before driving, read the label for drowsiness warnings, and if you're unsure, ask your pharmacist or let someone else drive. Never add a drink on top of it.
Check your understanding
Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
At what BAC level does the handbook say vision is already impacted for all drivers?
0.10%
0.05%
0.08%
0.02%
Answer: 0.02%
The handbook states vision is impacted at 0.02% BAC for all drivers, well below the legal 0.08% limit.
A driver regularly drinks to a relatively high BAC and shows no outward signs of impairment. According to the handbook, what happens to their crash risk at a BAC of 0.05% or higher?
It only increases above 0.15%
It decreases because they have built tolerance
It stays the same as a sober driver
It still increases without visible signs
Answer: It still increases without visible signs
Even without visible signs, drivers who compensate for drunkenness still increase their crash risk at 0.05% BAC or higher.