In the testing literature, the term load testing is usually defined as the process of exercising the system under test by feeding it the largest tasks it can operate with. Load testing is sometimes called volume testing, or longevity/endurance testing.
#1 Best Method: Caffeine. Drinking caffeine will help you stay awake while driving in a few ways. The first benefit is that caffeine is a short-term diuretic. This means it will make you want to go to the bathroom. Feeling uncomfortable is a benefit when trying to stay awake while driving and it will force you to make stops to go to the bathroom. Staying alive is worth the few minutes needed for the stops. Another unrealized benefit is the action of picking up the cup repeatedly.
The device has an on-board accelerometer. If the device sits still for 20 seconds, it goes into standby mode (lower heat setting, around 150C). Pick the device up or move it, and it will heat up to the last temperature setting selected. If the device sits still for 3 minutes, it will shut off. A bumpy car ride is enough motion to keep the device awake.