In the next six months, all three segment leaders — Chrysler, Honda, and Toyota — are due to launch new or extensively updated models.

Whether or not they are able to boost the image of this much-maligned vehicle remains to be seen.

Minivan sales have fallen sharply over the past decade as demographics, competition, and fashion have pulled customers elsewhere.

According to figures compiled by the Detroit News, minivan sales, which peaked in 2000 at 1.4 million, fell all the way to 434,000 last year.

The new models should reverse that trend. First out of the box for 2011 is the Toyota Sienna, the U.S.’s fourth most-popular van model.

Being Toyota, it chose not to reinvent the minivan but to refine it. The results are especially good news for more engaged drivers.

Reinvention means risk. The optimum shape for a minivan is a box, and every divergence from the optimum reduces the functionality of a vehicle that is all about functionality.

The other danger here is in trying to put lipstick on a pig. Nissan tried in 2004 to make over its Quest minivan for the “sexy soccer mom.” Consumers quickly saw through the artifice. Plagued by quality problems, the vehicle was discontinued after only five years of production.

Toyota flirts with disaster by outfitting the Sienna with a grille that has upturned trapezoidal corners and is flanked by extreme cats-eye headlights.  The result comes close to resembling a voodoo mask; you may want to exercise caution when parking the Sienna in the vicinity of small children.

Unlike Chrysler, Toyota doesn’t offer flat folding second-row “stow and go” seating. Instead it uses larger seats with more padding. Good call. Chances are you will spend more time in a minivan carrying passengers than you will cargo.

Toyota markets the Sienna in trim levels; the tester was the mid-level SE — the sporty minivan, if that’s not an oxymoron. It rides lower to the ground, and its electronic power steering is programmed for more immediate response and better road feel.

That isn’t enough to transform the Sienna into a sports car, but the SE strikes me as a smart compromise between practicality and panache.

It also is a lot of car for the money. The silver sky metallic test car carried a sticker with $33,490 on the bottom line. That’s with a 3.5 liter, six-cylinder engine producing 266 horsepower, alloy wheels, and seating for eight.

And lets not forget the “smoked, sport-trimmed headlights and taillights.”

The base Sienna with a four-cylinder engine (that’s the model used for price advertising that dealers never seem to have in stock) goes for $24,260. Top-of-the-line Limited models with all-wheel-drive, navigation, and entertainment systems can cost more than $42,000.

Navigating the bumps on Manhattan’s Henry Hudson Parkway, the Sienna felt jiggly and jouncey — like an old Buick. It was more at home on the twisty country roads of Litchfield County, Conn., where it navigated the corners with relative composure and easily handled the hills.

Every week seems to bring new revelations about quality problems at Toyota and the unwillingness of its Japanese executives to confront them. Aside from a few well-publicized incidents, however, the volume of actual occurrences has been few.

Now that the U.S. arm of the company, as well as its dealers, are on alert, the number of incidents should lessen. Besides the company is working hard to keep customers happy. I suspect it will be doing every thing it can to help the Sienna lead the minivan revival.