Loblogomy

When I read recently of someone’s disappointment that Wolfram|Alpha couldn’t tell them the average fuel efficiency of the Toyota Prius, I remembered I’ve been collecting this data since purchasing a Prius in January 2008, so I thought I’d share.

I have found that the Prius’s drive computer tends to overestimate fuel efficiency as compared to a calculation of real tank-to-tank MPG, but only slightly. After just over 14,000 miles, the calculated lifetime mean fuel efficiency for my Prius is 43.7 MPG. The lifetime mean currently reported by my Prius’s drive computer is 45.3 MPG, which represents a 3.6% overestimation. Not too bad. (Of note: Toyota advertises the Prius to get 48 MPG (city) and 45 MPG (highway), but as with all vehicles, those numbers come from testing in very controlled circumstances, and are generally a bit optimistic.)

When I was shopping for a new car last year, those familiar with my driving style were astonished when I told them I was considering a Prius. I, too, was worried that its 110 horsepower hybrid engine would leave me wanting more power, but I’ve been very pleasantly surprised. Sure, it would never make sense for me to try to beat, oh, say, a BMW M5 off the line, but I find that for everyday driving, the Prius has plenty of get-up-and-go. In other words, I can still pass all the idiots who insist on driving under the speed limit. And I can do so for less than 1/3 the fuel expenditure of the BMW.

The most amazing thing about the Prius isn’t actually the hybrid engine, though it’s still the most efficient drive train on the market right now. The Prius’s secret sauce is the user interface of its drive computer. It turns out real time reporting of your fuel efficiency does wonders for your driving style. You actually learn to drive more efficiently.

I find it somewhat peculiar that there’s so much volatility in the Prius’s tank-to-tank fuel efficiency, but I suspect that has something to do with my schedule—ie, when I’m very busy or have to be at the hospital earlier than I like to be, I tend to be a less patient driver, and thus degrade the fuel efficiency of my driving characteristics. I also suspect, but will never be able to prove, that the intertank variability was affected by the quality of fuel I purchased each time, which (I’ll also never be able to prove this) is probably less standardized than we’re led to believe.

All that being said, I am extremely pleased with the fuel efficiency of my Prius. Compared to my prior vehicle, I’ve saved about $700 in the past 12 months on fuel expenses. To be honest, though, that’s a somewhat difficult number to estimate given the fact that fuel prices have varied over 200% in the past 12 months. Had gas prices remained in the stratosphere, as they were just last summer, my savings would certainly be a bit higher.

If I had time, I could go on and on about how much I love the Prius, but suffice it to say it’s one of the best things I’ve ever spent money on. If you found this because you’re thinking about buying a Prius, stop thinking and just buy it. You won’t regret it.