The so-called "Ramp Jam" started Friday evening. The Sunset Boulevard off-ramp on the northbound 405 Freeway will be shut down for four months.
Caltrans crews are working to demolish the old off-ramp and finish a new ramp that is meant to hold 60 percent more vehicle traffic and will hopefully alleviate traffic troubles in the future. The new off-ramp will have two right-turn lanes and one left-turn lane.
"Ramp Jam" is part of the $1 billion 405 Freeway widening project, which is a year delayed and $75 million over budget.
Traffic is most likely going to get worse when the Wilshire Boulevard on-ramp to the northbound 405 Freeway closes on Aug. 22. The closure will last about three months.
The main detour is Sepulveda Boulevard. Metro recommends using Wilshire Boulevard or Moraga Drive to get around the closure. Officials say detours will be different day to night.