One of Los Angeles’ primary routes will be closed for 53 hours this weekend, causing fear of a potential gridlock among city officials.

The 405 freeway in Los Angeles will be closed starting in the evening of July 15 and remaining closed until the early morning hours of July 18. The closure is primarily due to demolition work on the Mulholland Drive Bridge. Both northbound and southbound lanes of the major north/south highway will be closed and Los Angeles city officials predict a “horrendous backup,” leading many to dub the closure “Carmageddon.”

(For a list of roads to avoid, the Los Angeles Times has put together this list to assist drivers).

City officials are asking drivers to plan ahead and use alternate routes, the Los Angeles Times reports.

“There’s gridlock on the 405 virtually any time of the day, but particularly during the rush hour, and if you think it’s bad now, let me just make something absolutely clear: On July 16 and 17, it will be an absolute nightmare,” said Mayor Antonio Villaraigosa, at a press conference warning motorists about the road closure.

“And that’s why we’re asking the public to plan ahead,” Villaraigosa said. “To avoid the area, to not go on the 405 or anywhere close during that period of time.”

The southbound 405 will be closed for 4 mi. between the 101 Freeway and the Getty Center Drive exit. The northbound 405 will be closed for 10 mi. between the 10 and 101 freeways. The work is part of a larger $1 billion freeway improvement project that includes constructing a 10-mi. northbound carpool lane to complete the highway system between Orange County and the San Fernando Valley.

Caltrans District 7 Director Michael Miles predicted a “horrendous backup” and a “really horrendous weekend.”

Drivers who might consider using Sepulveda Boulevard as an alternate route, should think again, officials said, because the road “does not have the capacity to accommodate both local and diverted freeway traffic.” Construction is also underway on Sepulveda and it is reduced to one lane in each direction during some hours.