What is the only reliable way to deal with becoming drowsy while driving a commercial motor vehicle?

Explanation

The only reliable response to becoming drowsy while driving is to get off the road at a safe location and rest or sleep before continuing, since nothing else actually restores the alertness that safe driving requires. Turning up the radio, opening a window, or drinking caffeine may feel like they help for a short while, but none of them reverse the underlying loss of alertness, and continuing to drive while fighting sleep raises the risk of a fall-asleep crash. What to do when sleepy while driving is a required CDL knowledge topic under 49 CFR 383.111(a)(20)(iii), but the regulation only names this as a required topic area; it does not itself prescribe the specific response, which is standard driver-safety guidance. The other options fail for a shared reason: each treats drowsiness as something to mask or wait out rather than a condition that requires the driver to actually stop and rest.

Source: 49 CFR 383.111(a)(20)(iii)