They're calling it Carmageddon. Only in Los Angeles, perhaps, could the prospect of a weekend road closure for improvement works invoke such alarmist warnings of impending doom. The LAPD even recruited some unlikely traffic wardens in the shape of Lady Gaga, Ashton Kutcher and Kim Kardashian - appealing to the celebrities to spread the word on Twitter to their millions of followers. Leave town now. Stay home. On no account venture outside. Be afraid. Be very afraid.

Why such a fuss about a few roadworks, you might ask? These aren't any ordinary roadworks. This is LA's 405 freeway, its main west side traffic artery, which is clogged by over half a million cars over the course of an average weekend. In a city that lives, breathes and dies by the car - no wonder the prospect of a 53-hour shutdown is depicted in these apocalytic terms.

So this weekend - officials are warning of gridlock - or a "potential paralysis moment". Fifty mile tailbacks, alternative surface routes completely jammed. They're preparing for the worst: hospitals on standby, fire crews deployed around the 13 most likely flashpoints. And there's more: special apps for smartphones, websites counting down the hours, the promise of free bus rides, though that's hardly likely to tempt the starried ranks of Beverly Hills.

The city has tried to tamper with it's freeways before - to its peril. Back in 1976 the transport authorities decided to impose a carpooling rule, reserving space for cars with one passenger or more. Unfortunately, the measure designed to reduce traffic ended up causing mayhem - deliberately so.

"We are prepared to endure considerable public outcry in order to pry John Q Public out of his car," insisted the head of Caltrans. (Loving that Q, by the way). Carpooling did, in the end, become part of life - but nothing would prise Mr Public from his precious motor vehicle. Entire books have been written to LA's love for its major roads, from the architecture to their soaring views. The essayist Joan Didion found meaning in their physical connectedness across a city with such a sprawling diaspora: freeways, she wrote, are "the only secular communion Los Angeles has." The critic David Brodsly went even further - describing the South California freeway as "the cathedral of its time and place". The car, then, as place of worship: traffic jams as a neccessary catharsis for the soul.

They've even become the stuff of television drama - not the scripted movies of Hollywood but the insta-thrill of the police chase - gleeful local news networks switching live to capture the latest fugitive motorist, with officers in hot pursuit. The all-seeing eye in the sky misses nothing, not your morning commute, nor your snuff-movie-style death-by-speeding-cop.

But this weekend, the giant neon signs are already flashing their warning, from hundreds of miles away: EXPECT BIG DELAYS. You could always walk - or buy a bike. But this is a stubborn place, where people drive two blocks to go spinning at the gym, where cars are left idling outside coffee shops while drivers queue impatiently for their double decaff non-fat soya macchiato. As the Carmaggedon website puts it - it's The Price You Pay to Live in LA. It's going to be a long, hot, couple of days.

Felicity Spector is a senior producer at Channel 4 News