LOS ANGELES (CBSLA.com) — The final part of the San Diego (405) Freeway overhaul begins Thursday night with a 90-day closure of the eastbound Wilshire Boulevard on-ramp.

KNX 1070’s Jon Baird reports the existing on-ramp to the northbound 405 Freeway will be demolished and replaced with one that can handle more than three times the capacity.

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Currently, the 824-foot ramp averages 8,000 vehicles per day.

Construction on the new 3,129-foot ramp has already begun, according to Metro spokesman Dave Sotero.

“They just need to fill the gap where the existing onramp is located now,” he said.

The ramp closure and construction is part of the $1.1 billion Sepulveda Pass Improvements Project slated for completion in summer 2014.”

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“It’s the last gap in the carpool lane here on the Westside of LA and when we’re done, we’re going to have a continuous carpool lane from Orange County and the valley in both directions,” Sotero said.

The eastbound Wilshire on-ramp will close at 10 p.m. Thursday.

Drivers were advised to use alternate routes, including:

– SB Sepulveda Boulevard to WB Santa Monica Boulevard to the 405
– Sepulveda to WB Pico to Cotner Avenue to the 405
– Federal Avenue and Westwood Boulevard to Santa Monica to the 405

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Traffic control officers will be in place at the Wilshire interchange during peak hours to direct drivers during the closure.