When the Toyota Prius hybrid became popular in the late 2000s, detractors labeled its angular, cut-off style ugly. In contrast, Motor Trend compared the sleek 2013 Tesla Model S to a "supermodel working a Paris catwalk."
So how can Prius owners drive around with the same degree of pride in their vehicle's awkward design as enthusiasts have for the sleek lines of the Tesla Model S?
As electric and hybrid vehicles drive into the consciousness of mainstream buyers, manufacturers are rethinking conventional approaches to their exteriors. They are discovering that one driver's four-wheeled ugly can serve as another's badge of honor. Long-held assumptions about what buyers want don't necessarily hold up.
The Nissan Leaf is a prime example of the unresolved tension between aesthetics, mass manufacturing and consumer psychology as the electric-car market evolves. When the company announced its plans to make the Leaf (the world's first mass-market electric car) form definitely followed function.
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For example, the headlamps (which protrude upward and outward) were shaped to reduce wind noise but have become a hallmark of the five-door hatchback's signature look. The car lacks a conventional front-end grille because an electric vehicle doesn't have a large engine and therefore has no excess heat.
"You don't have a grille, because you don't need a grille," said Andy Palmer, Nissan's executive vice president in charge of product planning.
Some design elements are simply for looks, though. Nissan details all its electric vehicles with blue chrome highlights, for instance.
"Carmakers are obsessive about badges, and we are no different," Palmer said.
The blue chrome highlights were a glance in the right direction but still not enough to impress Daniel Sperling, director of the Institute for Transportation Studies at the University of California, Davis, who admits to being put off by the styling of his wife's Nissan Leaf.
"It's not one of the better-looking ones," he said. Sperling said time to market played a role in limiting Nissan's aesthetic choices. "Part of it has to do with the fact that [Nissan CEO] Carlos Ghosn said publicly in 2010 that he wanted an electric car quickly."
Palmer doesn't necessarily disagree. New designs must have global appeal, he said, which is why the Leaf was created as a five-door hatchback. And rather than envisioning a futuristic beauty, he added, "we wanted to make it as inoffensive as possible."
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In 1999, the Honda Insight became the first mass-produced hybrid sold in the United States. Back then, the focus was primarily on getting the best gas mileage possible. With a highway EPA rating of 70 miles per gallon, the Insight was far and away the most efficient car on the market. But it was a two-seater, and its lightweight aluminum shell, teardrop shape, and covered rear wheels were not attractive to the average carbuyer.
"In the beginning, with the Insight, it was all about making it more efficient," said John Ikeda, who is in charge of advanced product planning for both Honda and Acura.
The second-generation Insight, which was introduced in 2009, features a more familiar exterior profile. The dedicated hybrid platform now accommodates five passengers and features a wedge-shape that many say resembles that of the early Prius. Insight also has one of the lowest suggested retail prices of any hybrid: $18,200.
Sperling compared the evolution of electric car design to that of computers, from clunky to sleek. He believes that many next-generation alternative vehicles will more closely resemble traditional gas-powered models.
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Since 2000, many auto manufacturers have introduced hybrid versions of gas-powered models, including Ford's Focus and Escape, GM's Yukon and Denali, and Lexus'upscale RX series SUV. Toyota has a hybrid version of its popular Camry sedan, Honda offers a Civic hybrid, and Hyundai delivered a Sonata hybrid.
It's just that you might have missed it. All these more traditional-looking hybrids have posted disappointing sales, in the low five figures. Meanwhile, the Prius continues to sell upward of 300,000 units a year in the U.S.
Is the Prius a a reasonably good indicator of what mainstream buyers are looking for in a next-generation vehicle? Yes and no: It is a reasonably good indicator of what half of next-generation buyers want.
Over the past two decades, Tom Turrentine, a research anthropologist and director of the California Energy Commission's Plug-in Hybrid and Electric Vehicle Research Center at the Institute of Transportation Studies at the University of California, Davis, has conducted surveys in which consumers were asked what they favored in the design of hybrids and other alternative vehicles.
In many surveys, half of those polled preferred that a next-generation car look like any other, whereas the other half wanted them to symbolize their new experience.
"They wanted the vehicle to communicate its attachment to the future," Turrentine said.
That thirst for the new is in stark contrast to the favored aesthetic among mainstream buyers: the past.
"Nostalgia is big in the automobile world," Turrentine said. After World War II, for example, people liked squared-off body parts reminiscent of military vehicles.
Ikeda at Honda said that innovative body styles "help everybody stir the imagination" and suggested that the mass-marketed vehicles of the future are likely to take cues from both traditional and unorthodox designs.
Honda's FCX Clarity, an all-electric car powered by hydrogen fuel cells currently offered by lease only in Southern California, Japan and Europe, looks like a cross between an Insight and a Civic.
How the vehicle is used will also inform future design trends. Is it a household's primary car—the one people fight over—or a second car used mainly used for errands and short commutes?
This divide will be key as companies come to better understand the interplay between consumer psychology and car consumption, Turrentine said. He has his eye on the BMW i3, the German automaker's all-electric vehicle, scheduled to arrive at U.S. dealerships in second-quarter 2014.
Though relatively small by American standards, the i3 features distinctive BMW styling, as well as the option of a small, gas-powered engine to help double its range of 125 miles per charge. The i3 is a five-door hatch, like the Leaf, and has been called the strangest car BMW has ever designed—which makes sense when one considers the still-evolving aesthetic in the alternative market.
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And consider this: Whereas the Leaf went sans grilles, BMW gave the i3 the two-grille look, otherwise known as the "kidney" radiator grille. It's a hallmark of the German maker's design aesthetic, even if the technology under the hood no longer requires it.
As for the "least offensive" Leaf, it won't be all that electric buyers see from Nissan, either. Palmer said its Infiniti LE all-electric concept car, displayed at the 2012 New York auto show, has elegant lines and sexy curves and just happens to have a better drag coefficient than the Leaf. Look for a consumer version of the LE in the next few years.
—By Alec Foege, Special to CNBC.com