I'll try to keep this brief.
A reader has brought the melodiously-titled "Shot In The Gas" to my attention.
Shot In The Gas's "Test Reports" page tells us that a truck achieved a massive 56% fuel-economy improvement when its fuel was treated with their liquid additive.
They say the truck was driven by a man called Brian.
And that's about all they say, as far as information about how well the test was controlled goes.
(There is, of course, also a page of testimonials. I don't see why they didn't put all of those on the Test Reports page, since they're all equally untraceable, and equally don't even pretend to be a properly controlled test.)
Apparently Shot In The Gas's products "have been tested for millions of driven miles" (emphasis theirs). But, as usual, nobody has at any point done any proper independent rolling-road, or even ad-hoc blinded, tests.
Such tests could unlock literally billions of dollars a year of income for whichever of the dozens, if not hundreds, of these miracle-fuel-additive companies actually turns out to be telling the truth.
But none of them ever do the tests.
The USA alone consumes about 380 million gallons of gasoline per day. That adds up to about a billion US dollars per day, even at the USA's low petrol prices, a bit more than $US2.50 per gallon at the moment.
If some miracle fuel additive reduced this consumption by a mere ten per cent, it'd be saving about a hundred million dollars a day, or around thirty-five billion US dollars per year.
(And this is just in the USA, and just gasoline. World petrol plus diesel consumption is of course quite a lot higher.)
But wait - Shot In The Gas have an explanation!
"This is not new technology. It has been around for 30 to 40 years". But "it wasn't cost effective to use the product until gasoline reached $2.00 a gallon".
Oooh, nice dodge!
Except... petrol has cost more than $US2 a gallon in most of the civilised world for, oh, a decade or three, right? I think petrol prices in the UK have, if you correct for inflation, never been below two US dollars per gallon. They've definitely almost never been below two inflation-adjusted UK pounds per gallon (PDF).
So even if Shot In The Gas hadn't been around to make a mountain of money in Europe for the last "30 to 40 years", one would presume someone would have.