Roadway Improvements & Traffic Advisories for September 10–17, 2025

City of Irvine sent this bulletin at 09/10/2025 08:15 PM PDT
Roadway Improvements and Traffic Advisories

September 10–17, 2025

In addition to the projects listed below that may impact your commute, you can find information on work being done to enhance our City on the Capital Improvement Projects Map and the Road Construction Map.

JOST Bridge Construction Impacts to the I-5 Freeway

As work continues on the Jeffrey Open Space Trail (JOST) Bicycle and Pedestrian Bridge, falsework steel beams and plywood forms will be removed over and across the I-5 Freeway. This will require multiple nighttime lane closures and full freeway closures September 8–26.

All work will occur from 9 p.m. to 7 a.m. Upcoming closures include:

Wednesday, September 10, and Thursday, September 11
Southbound Jeffrey Road off-ramp and southbound I-5 Freeway lanes closures.

Friday, September 12, and Saturday, September 13
Southbound I-5 Freeway full closure from Culver Drive to Jeffrey Road.

Monday, September 15, through Thursday, September 18
Northbound I-5 Freeway lane closures.

Friday, September 19, and Saturday, September 20
Northbound I-5 Freeway full closure from State Route 133 (SR-133) to Jeffrey Road and southbound
I-5 Freeway lane closures.

View the full construction schedule through September 26. Learn more about the JOST Bridge. 

Jeffrey Open Space Trail Bicycle and Pedestrian Bridge Map

Traffic Signal Shutdown at Culver Drive and Alton Parkway

The traffic signal at Culver Drive and Alton Parkway will be turned off or in red flash mode Wednesday, September 17, from 9 a.m. to 3 p.m.

Every effort will be made to keep traffic flowing and minimize disruptions, but delays should be expected, and motorists should consider using alternate routes when possible.

The work is part of an intersection widening project that will enhance traffic flow and improve traffic signal timing along Culver Drive and Alton Parkway. The project is expected to be complete this month. 

For more information, email pm@cityofirvine.org or call the project hotline at 949-724-6676.

Culver Drive and Alton Parkway Map

State Route 55 Off-Ramp Extended Closure

Orange County Transportation Authority crews are reconstructing the southbound State Route 55 MacArthur Boulevard loop off-ramp, requiring an extended closure of the ramp. The off-ramp will be closed and is expected to reopen to motorists by 5 a.m., Friday, September 19.

Detour signs have been posted. Motorists are encouraged to plan ahead before traveling through the area. View freeway detours.

State Route 73 Closures

The following nightly ramp closures in Irvine will continue on State Route 73 (SR-73) through Thursday, September 11, from 10 p.m. to 5 a.m.

  • Southbound SR-73 University Drive off-ramp.
  • Southbound SR-73 Bonita Canyon Drive off-ramp.
  • Southbound SR-73 MacArthur Boulevard on-ramp.

In addition, the southbound SR-73 Newport Coast Drive on-ramp will be closed through Thursday, September 11, from 10 p.m. to 6 a.m. Northbound SR-73 Bison Avenue on-ramp will be closed through Thursday, September 11, from 10 p.m. to 5 a.m. and Friday, September 12, from 9 p.m. to 7 a.m.

View detours as well as other work impacting The Toll Roads.

State Route 241 Overnight Closures

State Route 241 will be fully closed in both directions between State Route 133 and State Route 261, Thursday, September 11, from 9 p.m. to 5 a.m. and Friday, September 5, from 9 p.m. to 7 a.m.

View detours as well as other work impacting The Toll Roads.

Learn about additional projects throughout our City, including project descriptions and work hours, as well as any lane closures and night and weekend work, which may occur intermittently on major arterials when permitted.