25 Jan. 2007
SETI League
PriUPS Project


Today marks the last gas fill-up of my Prius hybrid in my second full year of ownership.  I mention the full-year aspect because gas consumption has a seasonal component, and because I had no ideal opportunity to comment after my first full year.

Happy Anniversary!

When I purchased the Prius it sported a sticker with the EPA mileage estimate of "51 Highway, 60 City."  Not only was this spectacularly economical, it was backwards.  Only cars of the hybrid persuasion get better mileage in the city than on the highway, the reason being that all that stopping and starting isn't as wasteful since the kinetic energy normally wasted by the brakes is instead banked in the electric battery.  Even though the efficiency of this process isn't spectacular, the lack of aerodynamic drag at city speeds allows higher mileage.

The EPA estimates have been criticized as being too generous because they don't reflect "real world" driving styles.  And indeed they don't.  I have little choice but to drive in the "real world," and I see all manner of wasteful driving activities.  People race to traffic lights and then brake.  I even see Prius drivers zipping past me as I drive at my sedate 55mph.  I suspect some of the least economical drivers are those who write reviews for the mainstream press, since they report the worst results.  If you check the Prius "chat boards" you'll see any number of folk who get (or claim to get) the mileage promised by the official ratings.  Frequently they are engaged in discussions with those who don't or can't who are wondering what they are doing wrong.  The answer, typically, is that they are driving as they used to, instead of adopting the real world to themselves. 

I have always understood that driving style is the most significant factor in gas mileage for any given vehicle.  And I was determined to eke out the best I could from the Prius.  I'm old enough that I don't care about beating other drivers from the light, and I take as much pleasure from calculating the best strategy to save gas as I do from the kick of acceleration in a high-powered sports car.  (Most of the time.  Once in a while I drive I high-powered sports car when I get the urge to guzzle.)  Most importantly for this blogitem, I have kept an accurate record of every single fill-up since the day I bought the car.

Here's the result

In about 42,000 miles of driving I have achieved an average of about 50 miles per gallon.  This is one mpg less than the EPA estimate.  It would probably be slightly greater than the EPA estimate instead, were it not for a major item not under my control:  I live near the top of a fairly steep hill, and it is impossible to recover the full amount of energy while going down that was added going up.  If my commute were on more-or-less level ground, it would be in the low 50s.  Additional factors not under my control are seasonal variations.  If we didn't have winter, that would probably tack on another mpg or two, as would a refusal to let my favorite leadfoot drive the car on occasion.

So There, Mr. Automotive Press!

I view getting excellent mileage more as entertainment than exigency.  My drop in the bucket isn't going to affect the oil crisis.  Far more effective should be my PriUPS project, if enough people adopt it.  But what can affect our national oil consumption would be a concerted effort of jawboning by the automotive press and those with influence to encourage people to drive economically.  It isn't enough to just buy a Prius; one must eschew the use of brakes!  It's not that hard.  And this is even more important for SUV and non-hybrid owners, since braking energy isn't recovered, and it takes much more gas to get them started back up, too.

An USDUC Moment

I've been asked to point this out by the United States Department of Unintended Consequences:  The EPA has decided to reduce their mileage ratings to what can be achieved under "real-world" conditions.  In other words, people will continue to drive as they always have, and they will get the mileage they expect, which will make them happy and prevent them from striving to improve their energy conservation skills.  This will waste gas and give CATWOKE more to whine about.  Bad EPA!  Naughty humans!

NP:  "Weep" - Reamonn

Richard Factor

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