Consider the 2006 Toyota Highlander Hybrid.

Anyone who has purchased a new-model hybrid gasoline-electric vehicle has probably based the decision on some or all of these things: fuel economy, environmental concerns, sociopolitical statements.

Whether buying a hybrid makes a statement is debatable, but it can be scientifically demonstrated that they are cleaner vehicles than standard cars.

Fuel economy also should be quantitative, but it has been controversial lately. Many owners of hybrids complain that their vehicles do not get the advertised 40 to 50 miles per gallon.

Blame it on cold weather, driving style, and a flawed EPA system for rating fuel efficiency. Still, hybrids do outperform their gasoline-only siblings.

The newest problem, as hybrid systems have moved into bigger vehicles, is that the price premium to own one has climbed into the thousands of dollars, even as the efficiency gap between the hybrid and traditional versions of the same vehicle has decreased.

Today's test vehicle is an example.

It had three rows of seats, a 3.3-liter V-6 engine mated to an electric motor, a continuously variable transmission (meaning virtually infinite gearing), and all-wheel drive.

The base price of $34,430 was about $3,000 higher than for a similarly equipped Highlander with standard gasoline power.

I have not driven a regular AWD Highlander in some time, but testing done by others has shown it is reasonable to expect fuel economy of about 19.2 miles per gallon.

During more than 1,000 miles of driving the Hybrid this month, I averaged 22.9 miles per gallon. That figure may be a bit low because most of my driving was in the suburbs and on the highway -- not on city streets, where hybrids perform better. Of course, who wants to rack up a lot of miles in the city with a seven-passenger, all-wheel-drive SUV? And I did not make any special effort, as some hybrid aficionados do, to maximize the hybrid technology. I just drove the rig.

So can you recoup your $3,000, given those performance numbers?

Yes, if you keep it a long time.

My calculations were made based on average annual mileage of 13,000 miles.

The standard Highlander uses regular gasoline, while premium is recommended for the hybrid.

At $2.117 per gallon for regular gasoline (the statewide average for Massachusetts last week), it would cost $1,433 to operate your basic Highlander for a year.

The Hybrid, running on premium at $2.363 per gallon, would cost $1,341.

That's a savings of only about $92 a year. Not exactly dramatic.

Still, if the nation's entire fleet of trucks and SUVs were to improve fuel efficiency by just three miles per gallon, lots of gasoline would go unburned.

And the Highlander has other things in its favor, such as room, performance, and ease of use. It is one of the finest SUVs on the market.

But I'm just not sure that using the hybrid system to maintain or increase power that we may not all need -- and Toyota is not alone here -- meets what should be a key hybrid goal: achieving significantly better gasoline mileage.

Manufacturers, in building today's standard gasoline-powered cars, have used important advances that, while giving us cleaner engines, also provide us with an increasing amount of horsepower, which is why overall fleet performance has not really improved in years.

Hybrids will miss the mark if they travel this same road.