Very good question! Really the only way is to be familiar with the basic physics/mathematics/engineering/software design practices. Clearly Sandy Monroe could tell but even experienced people can be duped. I spent a lot of time in my career listening to a wide spectrum of engineers with a wide spectrum of motives pitch a wide spectrum of proposals. I got pretty good at detecting BS. I have seen a lot of videos by this guy and he's not a BSer.So how do we differentiate the BS from fact?
The actual tests are SAE promulgated tests. The first step is to find out which ones of these the EPA demands. That's probably buried in some FAR. I haven't had much luck either. And if you find out the SAE procedure number you will find you will have to join the SAE to get a copy at what is still a pretty high price.I tried to find something from the EPA directly, but all they seem to publish to the public is fluff and nothing that spells out exactly what and how they test.
It never occurred to me to do something so obvious as write the EPA.