The transition ramp from the northbound San Diego (405) Freeway to the westbound Glenn Anderson (105) Freeway closed Tuesday night for reconstruction and will remain out of service for four months.
Crews will be demolishing and removing the concrete roadway surface. Caltrans will rebuild the roadway and the embankment and install a new drainage system.
As a detour, motorists were advised to exit the northbound 405 at either Imperial Highway or Century Boulevard and turn left toward Los Angeles International Airport. Motorists traveling from farther south should consider taking the Harbor (110) Freeway north to the 105 as an alternative.
Motorists should anticipate delays.
Caltrans officials said they scheduled the project in consultation with LAX officials in hopes of avoiding the airport's most congested periods.
The ramp from the northbound 405 to the eastbound 105 has been closed for about 14 weeks for reconstruction, but that transition road will reopen at 5 a.m. Wednesday.