As motorists age, they often want a few more pounds and several more inches of protection wrapped around them.

The full-size 2000 Buick Park Avenue sedan does just that, a long, wide, nearly 4,000-pound heavyweight.

As motorists age, they also demand easier entry and exit from the vehicle and lots of room to stretch the bones once inside.

The full-size Park Avenue delivers again, with wide-opening doors, comfy and cozy seats and sufficient space for heads, legs and arms.

As motorists age, they also want a trunk that will hold the luggage used on numerous and lengthy trips.

Park Avenue to the rescue one more time.

And as motorists age, they want an engine powerful enough to haul them and the luggage and still make it up hills without straining. And more important, an engine that will scoot them into the merger lane without hesitation when afforded only a small window of opportunity to join the crowd.

Yup. The Park Avenue again.

And for 2000, the full-size Buick sedan adds another benefit that older and mature drivers--in fact, drivers of any age--will appreciate: StabiliTrak, the stability-control system borrowed from Cadillac that senses when you are about to overdrive the limits of the car and are in danger of sliding or skidding. It slows and stabilizes the car to help you maintain control.

StabiliTrak earns its keep primarily on wet, snowy or icy roads as well as during sudden evasive maneuvers. It's a security blanket.

In addition to StabiliTrak, the Park Avenue Ultra we tested came with four-wheel disc brakes with anti-lock; traction control that regulates engine fuel flow as well as the ABS to bring a slippery or skidding wheel under control; variable-effort steering with higher pressure at higher speeds and lower pressure at low speeds, such as when trying to park a 4,000-pound sedan.

And there are dual front as well as side-impact air bags, the latter in the sides of the front seats so they move with you whenever the seat is motored forward or back, rather than housed in the doors where any seat movement can distance you from the protection.

Excellent package of features, further complemented by Gran Touring suspension designed with a bit firmer sho ck/spring settings and larger stabilizer bars to optimize handling in a large car without any offsetting ride stiffness.

And the supercharged V-6 serves a dual purpose. It provides 6-cylinder fuel economy for a 4,000-pound car (18 m.p.g. city/27 m.p.g. highway) when cruising along the interstate, but delivers V-8 energy when called upon to move those pounds quickly from the light, into/out of the passing lane, down the merger ramp or up the incline. And it performs quietly.

Tough to fault the Park Avenue, though we found a few flaws. The most noticeable is that the 113.8-inch wheelbase and 206.8-inch overall length has become perhaps more than a bit outdated. It appears, based on consumer preferences for so-called smaller, entry-level luxury cars, that what motorists want is the interior room of a Park Avenue but the exterior dimensions of a midsize Buick Century.

Park Avenue's size is OK if you have a three-car garage, and you park in the middle wit h nothing on either side. But when slipping between the lines in the vacant opening at church, we found we had to swing wide to get the nose pointed properly and the back end to follow the same path. At church you should always utter, "blessed be God," not "this blessed Buick . . ."

Also, because this is a full-size luxury sedan, it came covered with cowhide everywhere. If a few patches of cloth or suede had been applied to the seat back and bottom, the seats would not only be cooler in the summertime and less frigid in the winter, but they also would be less slippery in any season when making those evasive or emergency maneuvers that Buick thought necessary to control with StabiliTrak.

Upfront, our test car came with the optional "convenience" console, a $185 plastic mound that separates the front seats and forces buckets to replace a bench. Awfully big console, even if it does offer lots of goodies, such as flip-out-and-over cupholders and cell-phone holder, flip-up plastic writing tray, coin holders, power plug and stowage bins. A little slimmer design would be nice.

Last gripe is strictly personal--the name. Maybe when the next-generation Park Avenue appears it would be time to reach into the bag and come up with something fresh to denote a fresh vehicle. The LaCrosse, the name used on the Buick concept sedan of the future on this year's auto-show circuit, sounds nice.

The Park Avenue Ultra we tested starts at $36,800, which, if memory serves, costs only about $5,000 more than a much smaller Lexus ES300, which offers far fewer features as well as a lot less room--and no StabiliTrak much less supercharged V-6.

Standard equipment includes air conditioning with driver/passenger zone settings; 16-inch, all-season radial tires; remote keyless entry; battery rundown protection; cruise control; power foldaway mirrors; AM/FM stereo radio with steering-wheel controls; rear-seat pass-through to the trunk; heated power memory seats; power windows with driver express down; moisture-sensing wipers; daytime running lamps; power door locks with delayed locking when you engage "Drive" and power lockout so they won't engage if the key is left in the ignition; and retained accessory power.

>> 2000 Buick Park Avenue Ultra Wheelbase: 113.8 inches Length: 206.8 inches Engine: 3.8-liter, 240-h.p., supercharged V-6 Transmission: 4-speed automatic Fuel economy: 18 m.p.g. city/27 m.p.g. highway Base price: $36,800 Price as tested: $37,980. Includes $695 for chrome wheels, $200 for Gran Touring suspension, $185 for convenience console and $100 for radio upgrade to include CD and cassette and clock. Add $670 for freight. Pluses: StabiliTrak stability control system, traction control, four-wheel disc brakes with ABS, front - and side-impact air bags, supercharged V-6, massive trunk, automatic level-control suspension and about a gazillion creature-comfort goodies for a most respectable price, especially versus Japanese and European competition. Minuses: "Convenience" console bigger than a suitcase. About time for more sensible exterior dimensions to make it more manageable, such as when parking or garaging. >>