Resurrecting this thread as more work has been completed on SR 76 between Oceanside and I-15. The West Segment, between I-5 and Melrose Drive, was completed in 1999. The Middle Segment, between Melrose Drive and South Mission Road, was completed at the end of 2012. The East Segment is located between South Mission Road and I-15 and is divided into two phases. East Segment Phase 1 construction on the SR 76/I-15 interchange began in October 2012 and was completed in summer 2013. East Segment Phase 2 construction to widen and realign the roadway began in November 2014 and is anticipated to take about three years, finishing in fall 2017.
The project webpage contains maps and other details on the current project status: http://keepsandiegomoving.com/SR-76-Corridor/SR76-intro.aspx
The intended facility, upon build-out, will be (at minimum) a four-lane expressway with median barrier, bicycling improvements, and environmental improvements associated with the highway's proximity to the San Luis Rey River. Construction at this point continues on through 2016 to improve what is a very busy corridor, especially for traffic leading from Riverside County in the morning to Oceanside in the morning and the reverse in the evening. There are no plans to modify SR 76 into a full freeway at this time. The segment of SR 76 east of I-15 is not slated for the same level of improvements to be seen on the portion between I-5 and I-15.