Reply #94: not sure I follow this

[ngant17]

are you saying, then, that an infinitely-long vehicle will have an infinitesimally-small drag and improved MPG? If you put a sufficient number of cars following behind the truck, then according to your logic, it would remove the drag or reduce the drag from the lead vehicle (the truck).

It would seem logical that the longer the vehicle, the longer the drag. And a longer drag will result in reduced MPG.

Also, there is the law of diminishing returns that probably has to come into play somewhere along the line.

The bottom line, IMHO, is that you don't get something for nothing.

But even if what you're saying is true, it is a foolish and unnecessary risk to tail-gate a truck at +60 mph on the highway.

The best solution is to try and become mechanically-attached to the truck's rear bumper with some kind of super-magnet. In which case, you can turn off your engine and let the truck pull an extra ton or two to get yourself a true 'free ride'. Until the driver gets wise to the game and pulls over.