Final answer:
When feeling fatigued, a driver should stop driving and rest as it is the safest option to recover from sleep deprivation and avoid potential accidents due to impaired cognitive and motor functions.
Step-by-step explanation:
When a driver is feeling fatigued, the most effective and safe course of action is option 4: Stop driving and rest. Fatigue can impair cognitive and motor functions, similar to the effects of alcohol intoxication, and can increase the risk of accidents. While options such as drinking coffee or energy drinks may offer temporary relief due to caffeine, they do not address the underlying sleep deprivation and can lead to a crash in energy levels later on. Taking a short nap may also help, but only if it is safe to do so and it won't interfere with nighttime sleep patterns. Opening the windows for fresh air might momentarily increase alertness but does not substitute for proper rest. Ultimately, pulling over and resting is critical to allow the body to recover and reduce the sleep debt, ensuring a safer driving experience upon resuming the journey.