I’ve pretty much had it with the MPG figures I see quoted in automotive advertisements, and even “news” stories. Can someone please explain to me when Highway MPG became the standard for measuring fuel efficiency?

Once upon a time it was standard procedure to list MPG as City/Highway, like this – “23/28”

Then we had the great 2008 EPA Revamp of Everything Related to Fuel Efficiency. This update included new testing procedures to make the numbers more accurate for modern real-world driving. It also added a “mixed” rating so drivers wouldn’t have to guess where their car would fall between those city and highway numbers if they drove on both types of roads (which pretty much every driver does).

I welcomed all of these EPA changes, as they improved the clarity and validity of the fuel economy numbers featured on window stickers.

Unfortunately, the implementation of these new numbers has proven worse than the previous situation. Instead of the standard system of showing both city and highway miles-per-gallon figures we now have an accepted practice of quoting only the highway number in most cases, and occasionally only the city number when it serves an automaker’s purpose.

For instance, if the Chevrolet Cruze can attain 42 mpg under a fairly specific circumstance (an “Eco” model with a manual transmission driven only on the highway) all we hear is that the car get’s “…up to 42 mpg…” Conversely, if a Toyota Prius C gets 53 mpg in the city (but 46 on the highway and 50 in mixed driving conditions) we only hear it gets “…up to 53 mpg…”

I’m the most anti-government-regulation guy you’ll ever meet, but this is one area where I would actually support a federal law with regard to fuel efficiency claims. The law could be pretty simple (which is still very anti-government…) and simply state the following:

The dominant fuel economy figure to appear in any visual advertisements or vehicle specification charts, or to be quoted in any audio advertisements, MUST be the MIXED fuel economy figure.

The entire point of the mixed mpg figure in the current EPA rules is to provide a single number that is realistic and represents the most likely fuel efficiency number buyers will see in mixed real-world driving conditions. To have the number actually exist, yet never see it referenced in ads, is both misleading and a waste of valuable information.

So here’s something you’ll probably never hear me say again:

There ought to be a law!