This was the first Measure M project, completed in 1992, setting an ongoing Measure M precedent— finishing ahead of schedule and under budget. The project added High Occupancy Vehicle (HOV) and some auxiliary lanes from the 5/22/57 Interchange to Lambert Road. The HOV lanes were later extended into Los Angeles County. In early 2000, additional improvements were completed at the State Route 91 Interchange that added a direct HOV connector from eastbound SR-91 to northbound SR-57 and the reverse movement.
In an attempt to further increase capacity and reduce congestion on SR-57, a feasibility study was conducted by OCTA to examine alternatives for adding an additional lane in each direction between the Los Angeles County line and the 5/22/57 Interchange. This study concluded that because of extensive right of way impacts and expanded traffic at the 5/22/57 Interchange, any consideration of capacity improvements should be deferred until the SR-57 is extended southward toward the I-405 freeway. The study also recommended the corridor would benefit from operational improvements such as additional auxiliary lanes.
As a result of the feasibility study, a Project Study Report (PSR) was completed in 2005 for the following projects:
- SR-57 northbound from Orangethorpe Avenue to Lambert Road - Add mixed flow or auxiliary lane capacity.
- SR-57 northbound from the Katella Avenue on-ramp to the Lincoln Avenue off-ramp - Add auxiliary lane capacity.
The Orangethorpe to Lambert segment was the first project to be approved with the completion of the environmental phase in December 2007. The project is currently in the design phase and construction is scheduled to begin in Fall 2010.
The Katella to Lincoln segment entered the environmental phase in 2008 and construction is scheduled to follow approximately a year after the Orangethorpe-Lambert segment begins construction in late 2010.