NORWALK - Caltrans will fully close the southbound Santa Ana Freeway off-ramp at Pioneer Boulevard and Imperial Highway beginning Thursday at 8 a.m. The ramp will remain fully closed for eight months, through April 2014, when a new elevated off-ramp is complete and re-opens.

The work is part of the $1.6 billion project to widen the 5 Freeway by adding one general purpose lane and one carpool lane in both directions from the Orange County line to the 605 Freeway.

When completed, the new Pioneer/Imperial off-ramp will extend nearly 1,200 feet from the widened freeway and over Pioneer Boulevard, placing traffic on Imperial. Motorists will exit the new off-ramp using one lane before the ramp widens to three lanes.

During construction, southbound I-5 drivers will be redirected to off-ramps at Lakewood/Rosecrans; Florence Avenue; and San Antonio Drive.

To accommodate increased traffic demand on the San Antonio off-ramp, it will be restriped and a new signal at Union Street and San Antonio is being "modified."

Meanwhile, the $302 million I-5 HOV Imperial Highway and Pioneer Boulevard Project will widen nearly two miles of freeway by adding one HOV lane and one regular lane in each direction from Silverbow Avenue to Orr and Day Road. The bridges at San Antonio Drive, Imperial and Pioneer will be rebuilt to accommodate the wider freeway.

In addition to the new off-ramp at Imperial, other improvements include new sound walls and frontage roads. The contractor is Security Paving Inc.

The project is primarily funded ($167.5 million) by Proposition B, a 2006 voter-approved transportation bond. The project also received $104 million in state transportation funds and $30.5 million from Los Angeles County Metropolitan Transportation Authority (Metro) Prop. C and Measure R.

The project is overseen by Caltrans and funding is administered by Metro.

The public can sign-up to receive email notifications on freeway lane and ramp closures and local city street closures by calling (855) 454-6335 or online at i-5info.com.