Speed.

At last an action picture out of Hollywood that satisfies - the first since In the Line of Fire. It is called Speed, which refers neither to amphetamines nor to any record-breaking velocity. The speed in question is 50 mph, which is not likely to provoke many arched eyebrows or batted eyelashes. But it is the speed below which a Los Angeles bus must not drop if it is not to be blown to smithereens by a device an ingenious and monstrous sociopath has attached to its underside.

The film, written by Graham Yost and directed by Jan De Bont, impresses first of all by its very structure. It has a sort of prologue, a main part, and a kind of epilogue. But unlike other prologues and epilogues, each of these has enough action, chills, and suspense to outfit an entire movie. There is even a kind of topographical symmetry involved. The prologue features a stalled elevator that may explode with its passengers above ground. The centerpiece, as mentioned, involves a hallucinatory ride on the ground, in which all riders plus an intrepid cop who jumps into the bus may find their destination, unscheduled by the L.A. Rapid Transit System, to be Kingdom Come. And the epilogue goes underground, for a hellish subway ride, this time involving only the three principals, one handcuffed to a pole, the other two dueling to the death.

Good action movies are a reviewer's bane. How is one to fill out the allotted space without giving away too much plot? This is the sort of thing that stretches critical ingenuity to the breaking point, and sometimes beyond. The alternatives to telling too much of the story are to rehearse the director's and writer's previous credits, which can get pretty tiresome; or to rhapsodize about the actors, which is the stuff of fan magazines. So where does that leave us?

Film historians, perhaps, could make a go of it. They could tell you where Speed fits in the spectrum of cinematic thrillers between The Cabinet of Dr. Caligari and the many faces of James Bond. But that does not belong in this sort of publication.

Well, let me try to emulate the incomparable Pauline Kael, and see if I can analyze the personalities and audience appeal of the three main actors. First, the hero, Keanu Reeves. Last seen as the Buddha in Little Buddha - a catastrophe for all concerned - he has now happily transmigrated into Jack Traven, described as "an LAPD cop on SWAT detail." This is immediately engrossing: a hero with two acronyms (well, one bonafide, and one sort-of) pinned to him derives instant prestige, which Mr. Reeves makes the most of. A Canadian with a moniker that must be unique even in exotic Canada, Keanu (pronounced key-AH-noo) has an intense face with lean, limned features that would look great in intaglio or bas relief, but isn't half bad on the big screen either. For the longest time I used to get him mixed up with River Phoenix, not because they looked alike in the least, but because they were the two parallelly rising stars of their generation, and sported a vaguely similar aura. Now that poor Phoenix won't rise again, Reeves remains the undisputed champion.

Long locks, to be sure, do not suit him, which is partly why he was such a mess as Buddha. Here his close-cropped hair and sharply etched countenance, abetted by lithe, pantherish movements, stand him in good stead. Though a young man of action, he manages to look intermittently thoughtful: not slack-jawed and cow-eyed like Sly Stallone, or terminally obnoxious like Steven Seagal. Concerned but unsentimental, relentless in a good cause, and perfectly willing to shoot his partner in the leg if that will help apprehend the villain. As it happens, it doesn't.

As that villain, we have a past master, Dennis Hopper. When a part calls for wrongdoing, Mr. Hopper can do no wrong. Here he plays a fellow who wants $3.7 million to stop producing big bangs. Though foiled once, he may well succeed the next time: when it comes to explosives, he can blow away the competition. He is casual, even ratty; but his way of taunting the LAPD is crisply, precisely exasperating. Hopper is less maniacal here than usual, and the scarier for it.

As the obligatory young woman, there is Sandra Bullock, whom, wearing my theater-critic hat, I had singled out in an off-Broadway play, but whose first movie appearances were disappointing, until she came into her own in Wrestling Ernest Hemingway, and now this. As Annie, the free spirit who takes the wheel of the bus, she manages to be plucky, witty, and enchanting, very much the girl any man would want to sit next to on a bus. The writing for her and Mr. Reeves, humorous as well as taut, and absolutely natural, is in the best tradition of laconic lovers in action movies. It is one of several things that make the Canadian performer-writer Graham Yost, whose first screen feature this is, seem an enormously promising scenarist.

Of course, nothing about Speed can be taken seriously: it is lightweight stuff, and the multi-ethnic bus passengers are strictly a paper rainbow. But nothing about the movie bores; sneeze at that who dare! Jan De Bont, a fine Dutch cameraman who has been equally impressive in Hollywood, is also making his debut here as director, and proves, to use an appositely automotive epithet, smashing. With the help of the excellent Polish-American cinematographer Andrzej Bartkowiak, Mr. De Bont nudges the camera effortlessly into the trickiest spots (nooks, crannies, shafts, undersides - you name it), where it ferrets out every conceivable bit of added excitement. He understands that, to keep dubiety at bay, he mustn't ever slow down below 50 mph either. And he doesn't: this bus really delivers. As do the elevator and the subway.

* The Polish filmmaker Krzysztof Kieslowski's White, the second part of his color trilogy, is every bit as irritating as was the first, Blue; the third part, Red, has just been shown at Cannes, and augurs equally well. These are the three colors of the French flag, and the themes of the three films allegedly derive from the French revolutionary slogan: Liberty, Equality, Fraternity. Mr. Kieslowski likes these pseudo-profound schemas: he has also made Decalogue, a sequence of ten films about the Commandments, which I haven't seen, and the dreadful Double Life of Veronique, in which a dead Polish girl and a living French one are somehow corresponding alter egos. Blue, a maundering, meandering piece of complacent pretension about a woman whose composer husband died in a car crash and who is lethargically picking up the pieces of her not particularly shattered life, has very little to tell us about Liberty, and White does equally poorly by Equality, besides being preposterous on any level.

Karol, a Polish hairdresser in Paris, has married a Frenchwoman; they don't speak each other's language, and now Karol cannot even make love to his beloved Dominique any more. Why? No explanation. There is a divorce hearing at which his lawyers have to translate every word for him into Polish, even non. Divorce granted, Dominique owns every sou Karol had, and he, apparently friendless, spends the night in what is now her hair salon, where Dominique discovers him. They try to make love, but he can't. Furious, she sets the curtains on fire, and sics the police on him as an arsonist. He ends up in the metro, playing a Polish song on his comb and begging.

A Polish passerby, Mikolaj, takes pity on Karol and smuggles him back into Poland by plane, hiding him in his trunk (a likely story!). Bandits steal the trunk, are disappointed by its contents, and brutally dump Karol - of all places - near his home, where his brother is running the old hair salon. By a far-fetched stratagem, Karol appropriates a corrupt land-grabbing scheme from a pair of crooks (who don't kill him for it), and gets filthy rich, and no longer inept in the least.

Karol pretends to die, leaves all his money to Dominique, and books a flight to Hong Kong, where Mikolaj has bought a house for him. Dominique comes to Warsaw for the funeral, becomes all teary, and is overjoyed when, at night in her hotel room, the putative ghost of Karol turns out to be the real thing, with whom she now makes mad, magnificent love. Even his French is vastly improved. Hong Kong is forgotten, but by some absurd plot twist (engineered by Karol?), the police arrest Dominique for her ex's murder. In the last scene, Karol is let into the prison courtyard by night, carrying a pie for his love. Although Dominique couldn't possibly see him from her cell window, she mimes her love for him, and Karol beams. I tell you this plot so you can see how stupid it is; the details I omit are stupider yet.

But this wretched Krzysztof Kieslowski is considered a major director. Julie Delpy (Dominique) is a charming actress, and deserves better. Zbigniew Zamachowski (Karol) is a pudgy, slimy nonentity - and one of the most popular actors in Poland today. The co-screenwriter with Mr. Kieslowski is his usual collaborator, Krzysztof Piesiewicz, a lawyer, and thus presumably beyond feelings of shame. Mr. Kieslowski actually knows how to direct individual scenes, but I don't know why this should make people think he has anything to say.