Famous California interchange approved for $171 million reconfiguration

California Construction News staff writer

The California Transportation Commission has approved a $171-million project on to widen four miles and completely reconfigure a notorious interchange at State Route 46 and State Route 41 in California. The approved funding is about $40 million more than the original estimate.

The intersection is the location where actor James Dean was killed in a crash in 1955 and Caltrans says the reconfiguration of the triangle-shaped intersection will not impact a memorial to Dean set up about a half-mile away from the interchange.

Approval for additional funding was granted Dec. 7, because construction capital cost estimate “is greater than the programmed amount following the project’s refinement of the final design.”

The preconstruction services contract was awarded to a contractor during the middle of 2020-21 and several innovations were required including switching the pavement from continuously reinforced concrete to asphalt concrete, utilizing existing SR 46 when allowable instead of reconstructing near the eastern limits of the project, and optimizing embankment settlement strategies.

The department utilized 18 innovations developed by the Department’s Division of Design, CMGC, and Independent Cost Estimator (ICE) consultant to reduce the project costs by 28 percent (nearly $40 million) and received a 20-month allocation time extension in June 2022.

However, construction capital costs were underestimated due to the escalation costs the market has seen recently.

The biggest cost differences are related to the following items:

• Structures – increased by $12.4 million
• Earthwork – increased by $10.3 million
• Drainage items (Culverts, Inlets, and Ditch Paving) – increased by $4.6 million
• Environmental items (Landscape and Stormwater) – increased by $5.5 million
• Traffic items (Signs, Delineation, Barriers, and Electrical) – increased by $5.1 million
• Mobilization – increased by $12.2 million
• Time Related Overhead – increased by $9 million

“If the additional funds are not approved, the department will not be able to complete the conversion of the 2-lane conventional highway into a 4-lane expressway along this important transportation corridor,” staff wrote in a report. “The current time extension would expire, and programmed construction funding would lapse. A new project would need to be programmed to fulfill the intended purpose and need of the project. This delay would lead to an increase in cost due to escalation.”