Car Trouble Solved!

I've found a solution to my sleeping problem in the car...and train (yes, I found out that I also like dozing in the train as well). As soon as I know that I'm driving with someone (usually a relative) for more than 40 mins. I tell him/her that I am bound to pass out at some point in time. I've found the advanced warning suffices. So far I have been met with "oh okay, that's fine."

To be fair to the driver, I've done my best to avoid riding in the front passenger's seat as I've found that the primary duty of the person in that seat is to keep conversation going to keep the driver entertained.
But, yesterday on our way to Guinsa, I thought I could beat the ZZZs so I confidently sat in the front passenger seat of my uncle's car to chat and enjoy the mountains, rivers and lakes of Jecheon. Unfortunately, I overestimated my ability to keep my eyes open and the temptation to close them was just too much to bear and so, after about 45 mins. (even that was a bit of a struggle) I quickly informed my uncle that I was going to fall asleep. I leaned back and passed out.
My uncle, being the good man that he is, stopped by a beautiful river to gently wake me from my slumber before heading to our real destination. :) After a fifteen minute break, where I got to clear my head, we headed to the Guinsa Temple.

I wish I could have shared another solution to the car-train-sleeping problem, but alas! who knew that sleep could have such a strong hold on me? Until I find an alternative solution, this one will have to work.
I'm only sorry that I didn't get to use my "advanced warning" solution on the Karlinger family and Claudia...but I can assure you, they know now. haha. Oh, the problems I endure throughout my travels!