"National Lampoon's Vacation," a crosscountry comedy of calamities, is missing a sense of direction. With Harold Ramis in the driver's seat, it veers off course and sputters down a bumpy road.

Chevy Chase headlines as head of an average American family, California-bound -- object, an amusement park called Wally World. Chase, as comfortable Clark Griswold, has purchased an olive-drab family wagon, brand-new for the trip but rusty, dusty and dilapidated by the film's end. You might say it's a metaphor for the state of this picture, which is nothing but a vehicle for Chase's limited, but laudable, talents.

Chase, whose early efforts at acting revert to familiar anchor antics from "Weekend Update," is supported by Beverly D'Angelo as his long-suffering wife and Dana Barron and Anthony Michael Hall as the kids. Imogene Coca, as awful Aunt Edna, makes for some of the film's funniest moments, but she's not around to enjoy them, having died of what we can only assume was car sickness.

Death and disaster plague the vacationers as they take a wrong turn into a St. Louis ghetto, are thrown from a Magic Fingers wiggling bed in Kansas, bypass the House of Mud in Liberty and run out of cash at the Grand Canyon. All this to visit the home of a much-hyped cartoon moose. (Lampoons aimed at Mickey miss that esteemed Mouse by a mile.)

Pain is funny, often very. But Chase gets greedy with the laughs. Everybody's his straight man, even D'Angelo, who continues to act long after she has run out of part. The same goes for Hall as Chase's son Rusty and many in the cast. One smoldering standout is Jane Krakowski, as Cousin Vicki, one of a family of retards the travelers visit on the way. She, in her nasty nymphet's way, is much sexier than Christie Brinkley, being introduced with much hoopla in this film.

Brinkley, through no apparent fault of her own, is excess baggage. The open-faced cover queen plays a fantasy blond in a red Ferrari with "Luv Me" tags. As she passes the wagon, she comes on to Chase, mouth in a pout, hair in a blond hurricane. All this to set up a scene in which she struts her tanned stuff in bikini underwear and she and Chase skinnydip in a motel pool.

Nobody cares, though: not the kids, not the wife. She forgives him instantly. She's not jealous; she's not concerned because she has no real relationship with him. None have evolved in this script by John Hughes, not a story but a series of blackouts without a climax.

"Vacation" remembered to turn out the lights, but forgot to pack the wallop. NATIONAL LAMPOON'S VACATION At area theaters.