America's midsize sedans - the single largest group of cars most popular for work and family chores - are getting major makeovers, and the Nissan Altima is no exception.

A new fourth-generation auto for 2007, the Altima looks more distinctive than its predecessor, has a new platform and front suspension for improved handling, boasts a dressed-up interior and has achieved an overall best-for-Altima government safety rating.

But what's attracting attention from auto critics is the fact there's no traditional automatic transmission in the new Altima. Instead, buyers who don't want a manual transmission get a high-tech continuously variable transmission that they operate like an automatic.

Nissan officials say CVTs provide better fuel efficiency than many automatics, and, indeed, the new Altimas with CVTs have better government fuel economy ratings than their 2006 counterparts.

Even with the updates, the Altima's starting retail price has increased just $200 over the 2006 car. Starting manufacturer's suggested retail price, including destination charge, for a base 2007 Altima with 175-horsepower, 2.5-liter, four-cylinder engine and six-speed manual is $18,565.

This compares with the $19,090 starting retail price for a base 2007 Toyota Camry CE with 158-horsepower, four-cylinder engine and manual transmission and the $19,220 starting retail price for a 2007 Honda Accord sedan with 166-horsepower, four-cylinder engine and manual transmission.

Consumers aren't likely to notice that the 2007 Altima is 2.5 inches shorter, from bumper to bumper, than its predecessor.

What they do see is new headlamps - vertical in shape like those on the Nissan 350Z sports car - and a new, more expressive grille.

Taillamps at the back of the Altima are more prominent now, and fenders around the front wheels flare out to evoke power.

Look closely at those front wheel wells, and you'll see that the tires fit more snugly in there, with a reduced wheel opening gap around them. This is something BMW perfected over the years to make their cars look more sporting and substantial, and Nissan is catching on.

Overall for the Altima, the look is more notable than before, though it reminds me perhaps a bit too much of Nissan's flagship sedan, the Maxima, that starts at more than $28,000.

Both Altima engines are carryovers from last year, where they already topped their major Toyota and Honda competitors in horsepower and torque. But the uplevel 3.5-liter double overhead cam V-6 now develops 20 more horses - to 270 - and peak torque is 258 foot-pounds at 4,400 rpm, up from 249 foot-pounds. The test Altima 3.5 SE with CVT showed what this award-winning engine can do.

Though the five-passenger Altima with V-6 is virtually the same size as a 2007 Camry, the Altima seems sprightlier, with a stronger feeling of acceleration. The four-door car feels - and is - lighter, too.

The CVT was surprising because I could feel some shift points, including a kickdown to what seemed to be a lower gear right at startup.

CVTs, which are designed to operate within an infinite range of gears for maximum fuel efficiency, usually don't provide this sensation. But Nissan officials said they programmed their CVTs' software to make the Altima feel more ÒnaturalÓ and better fit driver expectations.

Indeed, they said the CVT used with the Altima's V-6 is, in particular, developed to give drivers better performance than an automatic might. For example, the CVT's controller ÒlearnsÓ how the car is being driven and remembers the driver's preferences for responsive power.

Alas, the recommended fuel for the V-6 Altima is the pricey premium unleaded gasoline.

The test Altima transmitted more road bumps to passengers than I expected. Though this fits with Nissan's goal of providing a performance feel, not a boring family car personality, it's a busier ride than what I found in the Camry and Accord sedan.

I also heard a good deal of road noise coming into the passenger compartment.

Power steering is new in the Altima and helped convey a good on-center feel in the test car.

Inside, the test Altima's optional leather on the seats looked and felt like real leather. It wasn't that stiff stuff that's difficult to differentiate from high-quality vinyl.

Seams and gaps on the dashboard are smaller than before, and I liked that the tops of the Altima doors, inside, were pleasing to touch. Nissan employed a new slush-molding material for these areas so they're not hard plastic.

Altima's 15.3-cubic-foot trunk is a tad smaller than last year's. But it's still larger than the 14-cubic-footer in the '07 Accord sedan and a bit more than the 15-cubic-foot trunk in the Camry.

Among the new Altima's standard features are six air bags, including curtain air bags and front-seat-mounted side air bags, as well as active head restraints on the front seats to try to prevent whiplash injuries.

But antilock brakes and vehicle dynamic control - also known as stability control - are options on some trim levels.

The 2007 Altima received five out of five stars for driver and front-passenger protection in frontal crash testing by the National Highway Traffic Safety Administration.

It received five out of five stars for front-seat passenger protection in side crash testing, too. Rear-seat passenger protection was rated at four out of five stars in side crash testing.

There is more Altima news coming. The company will soon begin selling its first gasoline-electric hybrid car, the Nissan Altima Hybrid.

And in the 2008 model year, Nissan adds a coupe version of the Altima.