Cars drive underneath the Mulholland Bridge on the 405 freeway in Los Angeles. (Jason Redmond/Reuters)

These realities help explain why a highway closure starting Friday on “the 405” has been already dubbed the “Carmageddon.” It’s the end of the world. Or at least the weekend.

For 53 hours, workers will close a stretch 10 miles northbound and four miles southbound on the freeway, which runs through the neighborhoods of L.A.’s most affluent residents. It’s expected to affect some half a million cars, the number of vehicles that normally travel the highway over a weekend.

The closure is happening as part of a $1 billion reconstruction project that will demolish an overpass bridge and expand the freeway, USA Today reports. The city hopes that by creating awareness about the shutdown, traffic will be decreased. The LAPD has even enlisted celebrities to act as Twitter traffic cops.

But Mayor Antonio Villaraigosa said he still believes July 16 and 17 “will be an absolute nightmare.”

Commuters trying to get from a freeway like the 10 to the 101 will have no way to connect. Those trying to get from the San Fernando Valley to the central coast will find it impossible to do so. Four big hospitals in Santa Monica and Los Angeles have complained that doctors, nurses, and patients won’t be able to get to emergency rooms.

Most people will try to take alternative routes, which will only worsen the snarls. “If you think you’re going to bypass the closure by some secret canyon route,” L.A. Police Lt. Andrew Neiman told USA Today, “you and a million other people have the same idea.”

The freeway is due to reopen by 5 a.m. Monday morning. Transit police promise no delays.

“It's a highly choreographed event,” L.A. County Metropolitan Transportation Authority spokesman Dave Sotero says. “By hook or crook, hell or high water, we will open the 405 Monday morning.“