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I-105 Express Lanes Plans, Specifications and Estimates

Reducing Traffic Impacts for Los Angeles County


During the design and construction of a $660 million Los Angeles Metro project to implement a new median lane in each direction from Sepulveda Boulevard to Studebaker Road, it was critical to maintain the corridor’s high index of truck traffic near LAX International Airport. The Plans, Specifications and Estimates (PS&E) across all phases of work had to overcome many obstacles to reduce the project’s impact on the traveling public.


This project included highway widening, bridge improvements, and local street improvements. When the highway was widened in the median, traffic was shifted to the outside to reduce impacts or traffic delays to LAX, the nearby commercial district, and the Metro C Line. To reduce the public impact of this project, innovative construction techniques such as rapid-strength concrete, precast pavement slabs, and Accelerated Bridge Construction were used. To improve vertical clearance issues on Central Avenue caused by the highway widening, traffic shifts allowed the road to remain operational in both directions during construction and were designed to accommodate the lower profile without impacting tie-ins to the existing tight-diamond ramps.

TRC provided PS&E solutions for this project including the construction staging and traffic handling plans, the Transportation Management Plan, construction area sign plans, and the layout sheets for five local streets impacted by the project, including Central Avenue, Imperial Highway, Fir Street, Bullis Road and Harris Avenue. We also designed and delivered the PS&E for widening the I-105 roadway by 25 feet to accommodate new lanes, including a weave lane at ingress/egress locations, additional auxiliary lanes at on-ramps, Express Lanes Direct Connectors where required, and reconstruction of outside shoulders to provide full structural sections in accommodation of travel lanes.


In close coordination with the LA Metro and Caltrans District 7, our solutions improved several local streets including a 2,200-foot reconstruction on Imperial Highway to adapt to the highway widening. Profiles of local roads throughout the 9-mile corridor were successfully lowered to improve the vertical clearance between the roadways and I-105.

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