What are some observable signs of impairment?

Observable signs of impairment are physical or behavioral indicators that suggest a driver may be under the influence of alcohol or drugs. Bloodshot eyes are often associated with intoxication as they indicate potential fatigue or the effects of substances. Slurred speech is a classic sign of impairment, as it illustrates a lack of coordination and control over motor functions, which can significantly affect a person's ability to drive safely.

The other options, while they illustrate certain states or conditions, do not indicate impairment. Clean clothing and an alert attitude suggest a person is in good condition and capable of safe driving, while routine vehicle maintenance records reflect responsible vehicle ownership but do not provide any direct observations of the driver's condition. Similarly, proper paperwork and a calm demeanor indicate that a driver is likely managing stress well, which does not correlate with impairment. Therefore, the signs of bloodshot eyes and slurred speech directly point to potential impairment, making this the correct choice.