The 2010 Insight, at first glance, fits almost perfectly into the Prius mold. The body has the same high-tail fastback silhouette, surely dictated by aero drag considerations. At 172.3 inches, the Insight is nearly three inches shorter than the Prius, 2.5 inches lower, and about an inch narrower. The space inside, as expressed by EPA passenger volume, is substantially less than in the Prius (85 cubic feet versus 96) and makes for a tight back seat with limited headroom. But cargo volume, at 16 cubic feet, is larger by 10 percent.

So much for the similarities. The behavior of these two hybrids is very different. “Hondas must drive like cars,” one engineer explained to us, citing a very specific difference: When you key on the Insight, the engine always starts. But when you power up a Prius, a ready indicator will glow on the dash even though the engine may choose not to start if it’s already sufficiently warm. This difference goes back to each company’s fundamental ideas about hybrids. Toyota’s hybrid is more complex, is more costly to build, and is capable of higher fuel economy in urban driving. The payoff of that technology, in fact, is sufficient to boost the Prius’s city mileage above highway mileage; Honda’s hybrids, like conventional cars, do less well in metro motoring.