MPG Is A Joke

The Way We Rate Miles Per Gallon Is Completely Broken

Today, though, almost all new cars have in-dash displays capable of showing a car’s real-time and average MPG, and very often those numbers don’t match what is on the window sticker. That means that everyone, not just those of us who got off on doing long division, could find out what their MPGs actually are in the real world. Sure, today we’ve added a third number, a combined average of the city and highway numbers, but really we’re still rating MPG as a solitary value.

And that’s the problem. The idea that two numbers (or, one “combined” number) give an exact idea of the sorts of fuel economy you can expect from your car is, frankly, ridiculous.

Fuel economy is absurdly hard to really measure with any degree of accuracy or consistency. The EPA actually does try very hard to get accurate numbers with their complicated testing procedures. Our own David Tracy goes into their whole process here in detail so you can see what I mean, but the truth is that a solitary value for MPG is a fiction, or, at best, only true for one specific set of driving conditions and for a particular driving style.

Now, the EPA is aware of this, of course, and they say as much on their Your Mileage Will Vary page because they know that, yes, of course your mileage will vary.

There’s no way it can’t vary, because there are so many different factors going on when you drive, and all those factors change, all the time: wind direction, tire pressure, weight in the car, temperature, road conditions, incline, driver adrenaline levels and on and on.

That’s why I think the EPA should abandon the city/highway/combined MPG rating system (even with hedge words like ‘up to’) in favor of an MPG range value. For example, my mother has a 2014 Fiat 500, one of those 1957 Edition ones, in mint green. It’s adorable. It’s an automatic, and she drives it like you’d drive a car through a roomful of kittens: slowly and gently. And honking a lot.

(Jalopnik.com)