Centennial Corridor Mainline


In partnership with the City of Bakersfield and Kern County, Caltrans is constructing a new Centennial Aerial Alignment for State Route 58 to provide a continuous route along State Route 58 from Cottonwood Road on existing State Route 58 (East) to Interstate 5. The project is known as the Centennial Corridor.


Contract Number: G3 # BK755
Value Phase 4 Construction Value $147 million
Type: Design-Bid-Build
Owner: City of Bakersfield
Location: Bakersfield, California
Duration 2019 to Present


The Mainline project, the fourth and final phase of the Centennial Corridor, constructs the freeway between State Route 99 and the Westside Parkway. The bridge structures are under construction at State Route 99, Real Road, Stockdale Highway, Ford Avenue, La Mirada Drive, California Avenue and Commerce Drive. At the SR 58 / SR 99 Interchange, a collector distributor on the northbound SR 99 will be added and a northbound to westbound connector will be constructed.


G3 has provided quality management inspection and materials testing services on this final phase as well as the previous two phases of the corridor. G3 is providing services for Class 2 Aggregate base, HMA-A, CRCP, JPCP and sound wall construction, including compaction testing and coring; concrete sampling; and laboratory testing at our facility in Bakersfield. Our ICC certified structural masonry inspector performed full time inspection during the construction of sound walls and sampled required CMU blocks, grout and mortar. The project quality program developed by G3 meets the requirements of the Caltrans standard specifications.


Our contributing value to this project includes our well-recognized City of Bakersfield and Caltrans experience, demonstrated ability to successfully manage complex construction schedules, including night and weekend shifts, and collaboration with project construction, engineering, and program management entities, all to ensure quality materials and practices are implemented to successfully complete this important highway improvement project.