Say "hybrid car," and most people think Toyota Prius.

The Japanese maker has sold roughly 3 million Prius models worldwide since 1997, which is more than half of all the hybrids in the world.

The 2012 Toyota Prius remains the gold standard among hybrid-electric vehicles, with three of its four separate models delivering a combined EPA gas-mileage rating of 50 mpg.

But there are more than a dozen other hybrids sold in the U.S. as well, and the technology will expand across many more vehicles in coming years as fuel-efficiency standards rise.

With that in mind, it's worth highlighting some hybrid models you may wish to think twice about before you sign on the dotted line.

2012 BMW ActiveHybrid 7

One of BMW's first two hybrid efforts--the other is the now-discontinued ActiveHybrid X6--the hybrid 7-Series sedan suffered from an unwieldy name, marginal gas mileage, and lumpy driving behavior that belied its "ultimate driving machine" image.

BMW skewed its first hybrid system toward boosting power, rather than improving fuel efficiency. In fact, the company touted it as "the world's fastest hybrid vehicle" at the time, with a 0-to-60-mph time of just 4.7 seconds.

2011 BMW ActiveHybrid 7

2011 BMW ActiveHybrid 7

The EPA rated the ActiveHybrid 7Li model at 20 mpg combined--no better than the (less powerful) conventional 740Li model the same year.

The hybrid's 15-kilowatt (22-hp) electric motor wasn't nearly powerful enough to move the full-size luxury sedan on its own. It could only contribute additional torque, restart the 455-hp 4.4-liter twin-turbo V-8 engine when the car moved away from a stop, and recharge the lithium-ion battery pack under braking.

We found that the car slowed noticeably when lifting off the throttle under 25 mph, "as if it had driven into mud that was dragging it down," when we tested the ActiveHybrid 7 two years ago."Worse," we wrote, "there's a perceptible second phase of recharging in which the car slows even quicker."

That's just not how a big, expensive BMW should behave.

BMW agrees. For 2013, the ActiveHybrid 7 is being updated with an entirely new powertrain that's shared with hybrid models of the 5-Series and 3-Series as well. It has a more powerful 40-kW (55-hp) electric motor and can move the car purely under electric power at low speeds, paired to a twin-turbo six-cylinder engine.

The update makes orphans of the 2011 and 2012 BMW ActiveHybrid 7. With fuel economy no better than a non-hybrid 7-Series, and notably worse driving behavior, we see no reason to put the 2012 model on your shopping list.

2012 Honda CR-Z

2012 Honda CR-Z

2012 Honda CR-Z

Fans of the legendary Honda CRX two-seater sports coupe really wanted to love the 2011 Honda CR-Z hybrid coupe.

But relatively few do.

The CR-Z is a perplexity, a mixed message. It's neither a light, lithe, roller-skate sports coupe like the 1984-1992 CRX, nor an ultra-economical hybrid with breathtaking gas mileage like the original 2000-2006 Honda Insight (rated at 53 mpg with a five-speed six-speed manual).

Instead, the hybrid system and a 700-pound weight gain to comply with modern crash safety standards (compared to the CRX) make it neither particularly fast nor particularly sporty.

We found it fun to drive, but only somewhat--and more because of its small size than any real sports-car character.

Honda does get points for offering the only manual-transmission hybrid model currently on the market. You can order the CR-Z with a six-speed manual as well as Honda's continuously variable transmission (CVT).

Gas mileage, at 37 mpg combined, is better with the CVT. The manual is rated at 34 mpg, little better than many four-door compact sedans with far more room and carrying capacity.

As a two-seater, the hybrid CR-Z is already a specialized vehicle. It's also the sole two-seat hybrid sports coupe on the market.

It will find some buyers, but it's not a very practical car. And its gas mileage isn't that special either, which puts it firmly on the "disappointing" side of our ledger.

2012 Honda Insight EX with Navigation

2012 Honda Insight EX with Navigation

2012 Honda Insight

The Honda Insight, a subcompact hybrid hatchback launched for 2010, was to be Honda's answer to the Toyota Prius. It even looks like a Prius in profile.

But its mild-hybrid system doesn't return gas mileage nearly as good as that of the Prius, which has the additional advantage of being much larger (the EPA defines it as a mid-size car).

The 2012 Insight's combined EPA rating of 42 mpg is 1 mpg better than previous model years, and it has a few equipment upgrades.

But the Insight suffers from sitting on the same showroom floor as the conventional Honda Fit hatchback, which remains one of the most flexible and spacious subcompacts on the market.

The Fit carries a base price more than $3,000 cheaper than the Insight, and is rated at 31 mpg combined with a five-speed automatic.

That means buyers really have to want a hybrid to choose the Insight over the more capacious, less expensive Fit.

So far, relatively few have. The Insight is another hybrid that hasn't come close to its original sales goals.

Honda is sticking with the car, making incremental improvements to its features and model mix.

But the Prius remains larger inside and delivers better gas mileage--albeit at a higher base price--while the Fit is larger inside as well and considerably less expensive if you're comfortable with a subcompact hatchback.

That puts the Honda Insight between a rock and a hard place.

2012 Lexus HS 250h

2011 Lexus HS 250h

2011 Lexus HS 250h

Sometimes the market doesn't lie: Cars that sell in low volumes just aren't very good.

That's the case with the Lexus HS 250h, now in the last of its three model years. It won't return to the U.S. market for 2013; instead, it's effectively being replaced by the all-new 2013 Lexus ES 300h mid-size luxury sedan.

When it was introduced as a 2010 model, the HS 250h was the first "dedicated" Lexus hybrid, meaning one that had unique styling not shared with a conventional gasoline model. (The Toyota Prius is another example of a dedicated hybrid; there's no gasoline Prius either.)

But the hybrid HS was awkwardly styled, with slab sides and lengthy overhangs. While it carried the more powerful 2.5-liter engine and powertrain from the Camry Hybrid, it also weighed 700 pounds more than a Prius--so managed only a 35-mpg EPA combined gas mileage rating, significantly less than the 50-mpg Prius.

More than that, the Lexus HS just wasn't very pleasant to drive. It felt slow and heavy, and although it was quiet inside under most circumstances, the engine howled under full acceleration--not what you wanted to hear in a mid-size luxury sedan starting at about $37,000.

Sales of the HS 250h never came close to Lexus targets its first year, and have fallen dramatically since then. Though it's leaving the U.S., it will remain on sale in other markets.

2012 Lexus RX 450h

2012 Lexus RX 450h

2012 Lexus RX 450h

This last one is a judgment call. The Lexus RX luxury crossover is by far the most popular model from Toyota's luxury make, comprising almost half of all Lexus sales in the U.S. last year.

The hybrid RX 450h model is often found in wealthy, progressive neighborhoods where its quiet, comfortable ride, the luxury appointments and features, and the subtle "Hybrid Synergy Drive" badge add up to discreet green-tinged luxury.

The problem is that quite a few RX hybrid owners report that they just don't get close to the combined EPA gas-mileage rating of 29 mpg.

We recently tested a brand-new 2013 Lexus RX 450h crossover--with a breathtaking, options-heavy sticker price of $58,060--and, indeed, got just 26.8 mpg over a 750-mile test drive.

The bulk of our mileage was at speeds of 45 mph or greater, where the hybrid RX crossover can't run solely on electric power.

Which brings home a crucial point: How you use a hybrid matters a lot to the gas mileage you get.

Spend most of your miles below 30 mph in stop-and-go urban and suburban traffic, and you really take advantage of the hybrid's engine-shutoff and all-electric running abilities.

But hammer out hundreds of miles on Interstate highways--as buyers often do on trips in the family crossover--and your efficiency will suffer.

We said the Lexus RX 450h is a judgment call because if you use it largely around town, you'll likely do OK on mileage. But be aware that if you're expecting to do a lot of high-speed trips, a diesel luxury crossover like the Mercedes-Benz ML 350 BlueTEC may give you better overall efficiency.


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