The Orange County Transportation Authority (OCTA) in cooperation with The California Department of Transportation (Caltrans) is widening the San Diego Freeway (I-405) between State Route 73 and Interstate 605. This project will improve 16 miles of freeway, along with the replacement and widening of over 18 bridges. In addition, this project will add the 405 Express Lanes, incorporating the existing carpool lanes and a new lane in each direction.
Please click here for an interactive map.
Please click here for the closure list.
For up-to-date information and construction updates, please visit the 405 Improvement Project Facebook page.
Full southbound (SB) I-405 closure between Seal Beach Boulevard and SR-22
SB I-405 Detour is:
EB SR-22 Detour is:
The closure is set for 11 p.m. Saturday, October 17, to 7 a.m. Sunday, October 18.
NB I-405 off-ramp to Seal Beach Boulevard to close for approximately one month
The NB I-405 off-ramp to Seal Beach Boulevard is scheduled to close for approximately one month. The ramp will be reconstructed as part of the freeway widening.
The ramp is scheduled to close at 5 a.m. Monday, June 29, and reopen July 29.
NB I-405 on-ramp from Seal Beach Boulevard closure
Crews are closing the northbound (NB) I-405 on-ramp from Seal Beach Boulevard during the day to continue pile driving activities for a wall adjacent to the ramp.
The daytime closure is set for 6 a.m. to 1 p.m. Thursday, June 18.
The detour is:
NB I-405 off-ramp to Seal Beach Boulevard
Contractors on behalf of the Orange County Transportation Authority (OCTA) will be conducting drainage work as part of the I-405 Improvement Project. Daytime closures are set for Tuesday, May 5th through Friday, May 8th between 6 a.m. and 4 p.m.