On a test drive of a Fusion Hybrid recently in traffic, I managed, without much trouble, to get 52 miles per gallon in mixed city-highway driving. Wait, so, has somebody invented the car of the future and didn't tell us? It's a worthy question. The scolding undercurrent of recent congressional hearings on the auto-industry bailout was the notion that Detroit had failed to invest in next-generation technology that could help wean us off of foreign oil. Not so. What they did fail to do was commercialize this technology sufficiently so that it was ready and waiting at dealerships when people got stampeded this year by spiraling gas prices. Had Ford made a few hundred thousand of these cars available in June -- along with the financing to sell them -- we'd be erecting 50-foot equestrian statues of William Clay Ford and Alan Mulally in city squares and the streets of Dearborn, Mich., would be repaved with diamond cobblestones. As it was, the meme of national incompetence and inferiority vis-a-vis the Japanese carmakers -- Toyota, Honda -- was reinforced again. Of course, Detroit can't build a desirable high-mileage car. We're the country that bungled Iraq and bred a Bernard Madoff, that turned the mortgage market into three-card monte and put Britney back on top. It would seem almost a shame to interrupt the soothing pleasures of such self-pity. And yet, here we are, with a car that seemed purely theoretical -- a desirable, affordable, no-compromise sedan that gets 40-plus mpg -- about to show up at Ford dealerships in the first quarter of 2009. Now what? Now people have to buy them. For all the game-changing glow around the Ford Fusion Hybrid, it's actually a fairly conservative and programmatic approach to gas-electric propulsion. The system is an evolution of the hybrid system in the Ford Escape. The battery is nickel-metal hydride, not lithium (lithium chemistry batteries are lighter and more energy-dense, but they are also expensive and finicky, which is to say, flammable). The nickel battery will please many in the green-car movement who claim that the search for the perfect battery -- a la the Chevy Volt -- has only delayed development of the good. (Edmund Burke said the worst thing a man can do is do nothing because he can do only a little.) The Sanyo-supplied battery pack -- 270 volts and 1.4 kWh, if that helps -- is 30 percent smaller in volume and 23 percent lighter than the one in the Escape. The smaller battery is easier to cool, requiring only cabin air ducted from underneath the back seat. The battery supplies enough glowing ponies to propel the car to speeds up to 47 mph on all-electric power. This is key to the car's in-city mileage. On my 50-mile drive, I was able to feather-foot the throttle enough to accelerate to commuting speeds without waking the gas engine. When I needed to accelerate faster, I could dip in to the engine horsepower briefly to overcome inertia, then maintain momentum with the electric motor. At one stage I was getting 63 mpg. To make a full-size car go fast on electric power alone, you need a boatload of voltage. But high-voltage systems involve increased impedance and heat losses, which is wasted energy. To unknot this problem, the Fusion uses a variable-voltage converter that temporarily steps up system voltage during peak demand or hard braking, when the battery is forcefully recharged. This is actually one of two high-tech converters on board: The second system provides juice to an array of high-voltage systems such as steering, air-conditioning and brakes. There's a lot of other arcane technology that goes into a car, like reams of software code that allows all the various components to talk sweetly to one another. But perhaps the most valuable bit of software is the wetware, the stuff between the driver's ears. To that end, the Fusion Hybrid uses a delightful, LCD instrument cluster with modules that coach drivers on how to save fuel. In one panel, the more lightly you drive, the more leaves that grow on a set of animated vines. You can go from lead-footed, gas-bingeing knucklehead (like me) to abstemious hyper-miler in a matter of minutes. Brilliant. So, is this the better mousetrap we've been waiting for? Well, there's a problem. The price of gas has dropped by two-thirds in six months, thereby de-motivating buyers who might have been willing to bear the incremental cost of a hybrid. What we really need is an increased federal gas tax, but the chances of that getting passed in Congress are comparable to my chances of being named Miss Universe. Ugh. I'm getting depressed again.