|
The flaw in the testing is not controlling for other variables. If you want to test the effectiveness of changing 1 parameter, that means all the other parameters have to be the same (speed, wind direction, wind speed, engine temperature, outdoor temperature, tire pressure....)
It's been shown that tailgate down is less efficient than tailgate up, but again your test doesn't sufficiently control the variables. The same road needs to be driven both directions for tailgate up and then again for tailgate down. There's no telling if there is elevation differences, a headwind or tailwind, etc. Driving both directions attempts to cancel the effects of elevation and wind.
|