We begin with lots of cool shots of Parisian parks and fountains as seen from above -- large geometric shapes are the visual motif. Nothing to do with the rest of the movie, but they're fun to look at. Then the camera goes indoors, focusing on a guy in a cubicle, Antoine (Jean-Pierre Darroussin), who bears more than a slight resemblance to the "Inconceivable!" guy from The Princess Bride. He's about to head off on vacation with his wife, but first, a beer. Or two. Or three. He can down 'em pretty quickly, but he'd tell you that it's all his wife's fault for showing up late.
Later, when the wife -- who goes by the name of Helene and is played by Carole Bouquet -- is taking a shower, Antoine heads out ostensibly to get gas for the car, but instead hits another bar and downs a double scotch. When they head out on the road, he keeps stopping for more double scotches. Given that he's not a big guy and can still manage to walk straight and talk coherently, he has to be one of the biggest alcoholics in the world. That's not a distinction I award lightly, either -- when you work in the newspaper business and hang out with journalists, there's plenty of drinking to be seen and experienced. But the way Antoine downs 'em, he could put most any hard-boiled reporter under the table.
Just for the record, though, wives don't tend to like that sort of thing. Especially if hubby is a mean drunk, whose general anger at traffic signals gets amplified tenfold when lubed with liquor. Eventually, Helene puts her foot down, telling Antoine that if he steps out of the car, she'll drive away. So he takes the keys, and she takes the train while he's inside making small talk with a big dude who looks like Ben Affleck trying to be a grunge rocker (Vincent Deniard).
There's also been some really obvious foreshadowing up to this point, in the form of radio and TV broadcasts telling us how bad and potentially lethal traffic is and how there's an escaped killer on the loose. Hmmm...you don't suppose the killer might cross paths with Antoine or Helene, do you?
Before we learn the answer, Antoine decides that the Affleck-looking guy must be the killer, despite no evidence that would suggest such a thing. Too bad he's already sharing the car with him. Affleck Guy (who isn't formally named onscreen until the very end) occasionally hits him, which certainly seems like something a fugitive would do, but Antoine's really annoying and not very sympathetic, so he kinda deserves it.
And this is the film's biggest problem. It's hard to generate suspense when the protagonist is a whiny drunk who deserves to get the crap beaten out of him. About halfway through the film there's a very drastic transition, and all of a sudden it's the next day. Antoine wakes up not knowing where Helene is, and he sets out to find her. To do this, he...makes a bunch of phone calls. Not good cinema, really. A bald drunk guy on the phone sits and dials a bunch of numbers in a scene that goes on forever. We still don't care about him, so it's hard to worry -- the only tension is wondering when it'll all end in the right call. Even then, information is withheld just to frustrate us, like a metaphorical version of the red lights seen early in the film and referenced in the title. But there's a line between suspense and mere annoyance, a line director Kahn is either flagrantly ignoring or just doesn't understand.
Or maybe he's joking. There's a funny running gag in which Antoine keeps running into crazy long-haired foreigners in bars. The first is a Spaniard yelling obscenities down the phone, the second a stereotypically imbecilic aging British rocker. It's possible that everyone in the film is intended to be such a caricature, but nonetheless, there's still little reason to care.