Once again, although lectures are appropriate for some instances and generally are appreciated, one DOES NOT have to keep unsafe distance from a truck to realize substantial benefits in energy consumption. The article referenced in your post notes that safe following distance is 150 feet at 55mph, which is equivalent to following interval of time of 1.86 seconds. As I posted above, 10-15% savings in energy consumption is easily achieved just by following truck with a safe interval of time, 2 seconds as I posted above. Note that this is more that what article claims the safe following distance is.
Just to clarify, I do not follow trucks as a rule, but knowing that you can do this safely, in a pinch, and how much of energy one can actually save, is something worth to keep in the back pocket. Beats reading lectures all the time.
Front of my car is covered with Xpell Ultimate, which does excellent job of protecting the paint.