The New Oxford American Dictionary has declared that "hypermiling" is the word of the year. As they explain,

“Hypermiling” was coined in 2004 by Wayne Gerdes, who runs this web site. “Hypermiling” or “to hypermile” is to attempt to maximize gas mileage by making fuel-conserving adjustments to one’s car and one’s driving techniques. Rather than aiming for good mileage or even great mileage, hypermilers seek to push their gas tanks to the limit and achieve hypermileage, exceeding EPA ratings for miles per gallon.

I've been interested in hypermiling and its mainstreamining, because I see its popularization (measured very nicely by its being word of the year, thank you OUP) as a really good example of what happens when digital information leaves cyberspace and becomes available in the world, and available in real time. We can see it in way drivers react to the Toyota Prius mileage estimator.

The Toyota Prius was a breakthrough in the hybrid auto market. If you live in northern California, they're almost a ubiquitous technology: you could be forgiven for thinking that Palo Alto passed a law requiring residents to own one. One of the most interesting features of the Prius is its fuel efficiency calculator (also called an MPG estimator). It appears on the screen in the center of the dashboard, and it tells you, based on how you're driving, your estimated gas mileage. Drive more aggressively, or accelerate quickly after stopping (thus engaging the engine rather than the batteries), and your mileage goes down. Drive more calmly, and the milage goes up. In other words, it provides real-time information about the impact a driver's habits are having on fuel efficiency.

Of course, we all watch our car's fuel efficiency, but the relationship between specific driving practices and efficiency is difficult to determine in conventional cars, or when calculating average MPG per tank of gas. With my car (a no-frills, late 1990s four-door sedan), I can easily calculate my average mileage is when I full up my tank-- just divide my trip meter reading by the number of gallons I've put in-- but the relationship between my actual driving practices and mileage is always hazy. Even if I fill up every few days (usually I can go a couple weeks between visits to the gas station), I can't make any useful connection between how much gas goes into my tank, how I've driven the last couple days, and what I could do to improve my mileage. I know I get better mileage on the freeway than the city (who doesn't know that), and that keeping my tires properly inflated helps (actually I don't know that, but enough people say it for me to believe it), but knowing that freeway driving is more efficient doesn't help me on my 2-mile commute to work, and I'm too lazy to reinflate my tires on a regular basis.

Prius owners have a completely different kind of relationship to their knowledge of fuel efficiency. By making information about fuel efficiency available in real time and in context, the Prius creates a feedback loop between a driver's behavior and MPG. As a result, it encourages drivers to change their driving habits.

Interestingly, many drivers describe efforts to boost their fuel efficiency as a kind of game. One driver, a former Silicon Valley tech executive and car afficionado, recalls that "When I got my Prius, it absolutely felt like I was piloting a large, rolling video game, seeing how to optimize the mileage." Another, a Valley educator, reports that driving her Prius has "become a game for me. I always try to improve the mpg over the last trip." When I gave my end of cyberspace talk at IDEO last week, I brought up the Prius MPG estimator, and one personal immediately said, "It's like a game!" Game designer Amy Jo Kim recalled, "When I first got my Prius 4 years ago, I was completely transfixed by the real-time MPG display. Multi-scale feedback! I could see my mileage per tank, in 5-minute increment, and moment-to-moment. I experimented with my driving style, trying to beat my "high score" each day." A 2006 Cnet article described the Prius as "a mobilized video game... surely the most expensive, biggest gaming machine built... so far."

This kind of feedback has always been an attraction of expensive, high-performance cars. Sports cars give you a feel for the road, and let you hear and feel how well the engine, transmission, and brakes are performing. "In many ways," one friend e-mailed me, "driving the Prius is just as much fun as my little red sports car: there is a ton of feedback, which encourages very intense involvement with what the car is doing; it's just that the involvement takes very different forms in the 2 different cars." He adds, "The typical sports car communicates tactilely, via the driver's hands, skin, eyes, and ears... that's why it is such a joy to drive. Communication with the Prius is mostly via eyes and ears, but there is a similar quantity and quality of information; the driver is just optimizing different things."

The Prius-as-game metaphor may make the car, and the behavioral changes it inspires, more appealing to young drivers. Another Silicon Valley Prius driver told me, "the biggest impact our having a Prius with its MPG feedback has had is to make our son a pretty careful driver. When I was a teenage driver, my focus was acceleration, his is efficiency. He has learned to tell by feel when the gas engine is on and can achieve better MPG results than either of his parents."

The Prius MPG estimator shows how the presence of real-time feedback can encourage changes for the better in user behavior. In effect, it makes the extreme engineering sport of hypermiling accessible to a broader public. Hypermiling is a set of practices that a small band of drives have developed to substantially boost their cars' fuel efficiency. They range from fairly straightforward-- e.g., accelerating slowly, avoiding stop-and-go driving-- to the extreme-- e.g., switching off the engine while drafting behind tractor trailers.] Hypermiling is an interesting combination of low tech and information intensivity. Many hypermilers are engineers or scientists-- Wayne Gerdes, who coined the term "hypermiling," is a nuclear power plant operator-- who treat their cars with the empirical and quantitative scrutiny they apply on the job, and have carefully analyzed the physics of driving. At the same time, most hypermilers don't radically customize their cars. Instead, as Dennis Gaffney reports, they take the position that "fuel efficiency is not about the car. It's about the driver." Successful hypermilers don't get "high mpg marks by tinkering with engines or using funky fuels or even, most days, by driving a hybrid," but "by driving consciously—hyperconsciously."

Prius owners talking about the "game" of increased fuel mileage also illustrates how many users naturally construct narratives and cognitive frameworks around interactions with technologies. Toyota didn't intend for the Prius to be thought of as a game, but owners happily think of it as such. Just as Internet users in the 1980s and 1990s quickly came to talk about going online as akin to going to a place, Prius owners reach for a familiar technology interaction model to describe this new kind of interaction. This suggests that designers of systems for revealing real-time energy use might want to borrow some visual cues from video games, but needn't construct complicated narratives or rewards for good behavior: users will fill those things in themselves.

Hypermiling illustrates how monitoring fuel consumption, understanding the physics of driving, and applying rules (some of them not particularly safe) for more fuel-efficient driving, can substantially boost fuel efficiency-- in short, how information can be exchanged for energy. However, hypermiling is a lot of work, as it requires generating and tracking information that the car itself may not provide. With the introduction of real-time fuel mileage calculators on cars, however, hypermiling practices are starting to reach a wider audience. More widespread adoption of fuel efficiency calculators could also have a significant impact on oil consumption. Hypermiling pioneer Wayne Gerdes argues, "If the EPA would mandate [fuel consumption displays] in every car, this country would save 20 percent on fuel overnight.... They're not expensive for the manufacturers to put in— 10 to 20 bucks— and it would save more fuel than all the laws passed in the last 25 years. All from a simple display."