FILM / Picture that majors on motion: No characters, no motives, no trickery: 'Speed' is a film like no other, and a hit. Mary Harron talks to the people behind it

IT IS safe to bet that none of the Hollywood executives behind Speed has ever been on a bus in Los Angeles. No one in Los Angeles takes the bus; no one, that is, with the slightest access to money or power or position. Those who do are the working poor, mainly black and Hispanic. They wait at the stop slumped in resignation, knowing they are excluded from the city's rapid pulse, knowing that if a bus ever does arrive it will take hours to crawl downtown. One of Speed's many in-jokes is its title.

Speed began in 1991 when aspiring screenwriter Graham Yost had a simple, but perfect, idea. There is a bomb on a bus. If the speedometer goes above 50 mph, the bomb will be primed. After that, if it goes below 50, the bomb will go off. The idea owes something to Kurosawa's Runaway Train, or you could see it as an airhead version of Clouzot's Wages of Fear, in which all tension is focused on a moving vehicle, its spinning wheels, its speedometer and the obstacles ahead. Hollywood studios specialise in ruining simple ideas, and perhaps Speed was lucky that no one took it very seriously. It wasn't an A-list picture like the summer's other big action hit, James Cameron's True Lies, which had Arnold Schwarzenegger, a dollars 100m budget and enough hardware to relaunch Desert Storm. Instead, 20th Century Fox cast Speed from the B list, and hired a first-time director, Jan De Bont. A celebrated cameraman who had begun his career in Holland, De Bont, now 50, shot most of Paul Verhoeven's movies, including Basic Instinct, and was director of photography on innumerable action pictures (The Hunt for Red October, Black Rain, Lethal Weapon 3), including the best one of the Eighties, Die Hard.

When De Bont first heard about the project, he went to Fox and pleaded for it. 'I knew I could really do something with it because it's pure excitement, it starts on a high level and just escalates. I wanted to make it rough, pure - not high-style, because then you'd lose the power of this big dumb bus.'

Meanwhile, Yost's screenplay went through what he estimates as 17 versions, including 10 major rewrites. The hero, Jack Traven, is a policeman who, taunted on the telephone by the bomber (Dennis Hopper), boards the bus and sets about saving the passengers' lives. In the script's early stages, Traven was burdened with guilt over the death of a hostage and tormented by his relationship with his authoritarian father, also a policeman. Hollywood action heroes are always tormented. It puts a redemptive gloss on all that random slaughter by giving the violence a purpose: to enhance the hero's self-esteem. It also makes actors and writers feel better, giving an impression of complexity - even though what passes for psychology in Hollywood is often banal and formulaic.

De Bont wasn't having any of that. 'People always say you have to know the character's background, you have to understand his psychology. The audience doesn't need all that bullshit. We learn everything we need to know about the characters from how they react to things.'

Jack Traven, too, was changing with the script. He began as a wisecracking thirtysomething cop: Bruce Willis, say, or Mel Gibson. For a while he became black, as Denzel Washington and Wesley Snipes were offered the role. But he ended up as a Canadian / Hawaiian dreamboat with a limited range of expression: Keanu Reeves. 'Denzel would have got dollars 5m; Keanu probably got dollars 1m,' estimates Yost. (It was a bargain; following Speed's enormous success, Reeves is now said to command dollars 7m.)

'I thought of Keanu after I saw him in Point Break,' De Bont says. 'He's young, he has a vulnerable quality - open, romantic. To me, Keanu - if you had a daughter you'd let him take her out. A little old-fashioned, chivalrous.' There is a passivity about Reeves that makes him perfect for a new kind of role: the action hero as New Man. A key element in the sexual dynamic of Speed is that it is the heroine, Sandra Bullock, who actually drives the bus. There is no good reason for this. When the driver is injured, Jack Traven just picks the most attractive female passenger and asks her to take over. She drives magnificently and he looks on, adoring and supportive, and occasionally does something life-threatening to show he's a man.

Not much of Speed's plot stands up to close examination, but De Bont argues that logic doesn't matter if you can keep the action moving. The filming was run like a military operation. A real freeway was out of the question so the production team had to create their own. They found a stretch of freeway that was still under construction and finished it for the city. ('We painted the stripes on the road.')

Then they laid on a fleet of 500 cars, driven by extras, to simulate freeway traffic. The cars were divided into squads of 25, each with a group leader, and directed by their own AM radio system. Still, there were problems: if just one car broke down and caused traffic to snarl, all 500 had to go back and start again.

Having cut the picture loose from motivation, De Bont now freed it from acting. Whenever possible he wanted the stunts, and the actors' reactions to them, to be real, refusing the help of special effects. Many of the scenes were done in one take, with multiple cameras hidden all over the bus. 'I'd have two cameras on Sandra, one on Keanu, maybe two on the passengers. I planned it very carefully. I hid the cameras behind passengers, between seats, on the walls. Maybe if you replay a scene in slow motion 20 times you can spot one.' There were two steering wheels, a fake one inside the bus and the real one on top with a stunt man driving. In one key scene the bus turns off the freeway and into a side road, only to find a truck blocking its path. 'I didn't rehearse the actors for that scene. I told them something was going to happen, but I didn't say what. When Sandra starts screaming 'Get out of the way' at the truck, that's not in the script.'

The key to De Bont's handling of the picture comes in the opening minutes, when a car flies over a bump: a homage to Bullitt, the Steve McQueen car-chase film of the Sixties. 'In the last few years action pictures have gotten bigger and bigger and more and more expensive, as if you blow up more, you crash more, you'll make a better film. I wanted to do something like Bullitt, just a plain good story that follows one guy and tries to stay close to reality.'

Speed is both very old-fashioned and very new. It is the year's most abstract adventure film: most of the genre's usual attributes are stripped away. No chase sequence. No big stars. No special effects. No motivation. No wonder Keanu Reeves stepped so easily from Little Buddha to Speed: this is pure motion, the action film as Zen.

This is a time of extraordinary freedom and vitality in American film, at least in the independent sector where no subject is too outre and no tech too low. The year's best films have included Spanking the Monkey, a black comedy about mother-son incest, Go Fish, a romantic comedy about young lesbians, and Clerks, a hilarious movie about two deadbeat clerks in a convenience store, with a plot that embraces necrophilia. Shot in murky black-and-white for only dollars 27,000, financed, like so many indie films, with a fistful of credit cards, it has been picked up for distribution by Miramax.

In American movies today you can be experimental on a shoestring or you can be mindlessly violent at huge expense. But where are the comedies and the thrillers of the past? Somewhere in that forgotten middle ground of entertainment, where Hitchcock and Howard Hawks used to play, is Jan De Bont's big dumb bus, endlessly travelling its artificial freeway.