ORANGE – The county’s transportation board on Monday awarded a $1.2 billion design-build contract – the largest in the agency’s history – to add one regular lane in each direction and an express lanes toll facility to relieve traffic on the I-405.

Upon completion of the I-405 Improvement Project, travel time on the highway from State Route 73 to I-605, consistently ranked among the busiest in the nation, is expected to take 29 minutes during rush hour and 13 minutes on the 405 Express Lanes, by the year 2040, according to a study by the Orange County Transportation Authority Environmental Impact Report.

Without the project, driving the same stretch is projected to take 2 hours, 13 minutes in regular lanes and two hours in the carpool lanes.

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OCTA board members, by a 14-0 vote, selected OC 405 Partners – a team of firms led by OHL USA Inc. and Astaldi Construction Corporation – which offered the lowest price for the job of three qualified bidders.

“The bottom line is, we got the exact road we’ve asked for at the exact price we think is fair and we can actually pay to build this road,” OCTA board member Jeffrey Lalloway said.

Monday’s milestone makes the I-405 Improvement Project the first in California that will be built following the passage of AB 401, which allows regional transportation agencies and Caltrans to use a design-build method to deliver highway projects in a way that reduces time and cost.

The OCTA began studying the busy corridor in 2003 and “that set the stage for this being one of the centerpieces” of Measure M, the county’s half-cent sales tax for transportation improvements passed in 2006, the authority’s CEO Darrell Johnson said.

Construction is slated to start in early 2017 with the new regular and express lanes at the center of the highway opening in 2023.

“I’m fully confident that we will have the team capable to design and construct this project in the next 5 1/2 years to the satisfaction of the public and the agencies that we work for,” Tony Bagheri, executive vice president for OHL USA Inc., told board members.

Earlier on Monday, the OCTA board, with more members participating, approved by a 15-1 vote on a toll operating agreement with Caltrans for the I-405 project. The agreement covers design, construction, maintenance and operation of the express lanes.

The I-405 Express Lanes will be the first project in California to use the tolling authority provided last year under AB 194 that ensures that any excess toll revenue will be used to fund improvements on local streets and public transportation.

Gary Miller, the sole dissenting vote on the board, asked for a substitute motion for the corridor to be more clearly defined so any excess revenue would have a local benefit and not stray to more distant areas.

“You couldn’t have local agencies use the toll facility to offset bus operations 40 miles away,” Johnson clarified. “It’s improvements for all modes within the corridor.”

In addition to building new lanes, the I-405 project includes constructing 18 bridges and improving access to highway and traffic on surrounding streets.

Litigation over mitigation factors and the environmental impact report continues with the cities of Seal Beach and Long Beach, OCTA spokesman Joel Zlotnik said.

Contact the writer: 714-796-7762 or jkwong@ocregister.com or on Twitter: @JessicaGKwong