Here’s the press release from Caltrans:

The California Department of Transportation (Caltrans) will fully close South Firestone Boulevard in both directions from Rosecrans Avenue to just south of Silverbow Avenue  beginning on Monday, December 9 at 6 a.m. and continuing through April 2014.
The work involves  demolishing the existing roadway and reconstructing S. Firestone Boulevard and realigning the intersection of Bloomfield Avenue and Rosecrans Avenue.

Detours will be posted and digital portable message signs are in place to notify the motorists. Residents and emergency responders will have access at all times during the closure.  Noise will be experienced from back-up alarms, work crews and other related equipment and water trucks will be on-site and used to minimize dust during working hours.
Wednesday, December 4 – to prepare for the long-term closure on Dec. 9, crews will move cranes and equipment into the work zone during overnight hours.   The following streets and ramps will be fully closed overnight on Wed. Dec. 4:
Local Streets:
8 p.m. to 6 a.m. –  So. Firestone Blvd., from Bloomfield Ave. to Carmenita Rd.
–  Shoemaker Ave. from South Firestone Blvd.  to Excelsior Dr.
10 p.m. to 6 a.m. –  Eastbound Rosecrans Ave. from Bloomfield Ave. to No. Firestone Blvd.
Freeway Ramps:        
9 p.m. to 6 a.m.  –  Southbound I-5 on-and off-ramp at Rosecrans Ave.
–  Northbound I-5 off-ramp at Rosecrans Ave.
The work is part of the Santa Ana Freeway (I-5) South Corridor Improvement Projects extending nearly seven miles in both directions from the Los Angeles/Orange County line to I-605 to widen the freeway, bridges and overcrossings and add one High Occupancy Vehicle (HOV) lane and one general purpose lane.

The public is encouraged to sign-up to receive email notifications on freeway lane and ramp closures and local city street closures by calling the I-5 South Corridor Improvement Projects Toll-Free Hotline (855) 454-6335 or by visiting www.I-5info.com

Traffic Information:  For timely, accurate and accessible real-time traffic information:
Caltrans Quick Map http://quickmap.dot.ca.gov/  Caltrans Quick Map
Caltrans Lane Closure System:  www.lcswebreports.dot.ca.gov