Metro LA Congestion Reduction Demonstration Project, Los Angeles County, CA
Metro LA Congestion Reduction Demonstration Project, Los Angeles County, CA


Metropolitan Transportation Authority (Metro)

Completion Date

September 2011

DYA Client


Project Description

The project consists of converting existing high-occupancy vehicle (HOV) lanes along I-10, I-110, and I-105 within the County of Los Angeles to high-occupancy toll (HOT) lanes.  The scope of services included design-build requirements for the toll systems, civil work that included widening of the Adams Boulevard off-ramp, a pedestrian bridge overcrossing, other freeway‑related efforts to support the toll systems' integration (to include tolling equipment, customer service centers, and back-office operations), and the operations and maintenance of the project for a minimum of one year.

Diaz•Yourman & Associates (DYA) provided geotechnical services for several portions of the project, including review of the foundation report for the Adams Boulevard pedestrian overcrossing bridge structure; performing a geotechnical investigation, laboratory testing, and analyses; providing recommendations for the Adams Boulevard off-ramp widening, additional signage structures, and bridges; and reanalyzing the existing sign structures, pavement recommendations, and an aerially deposited lead study.  We also reviewed and made recommendations for construction on all proposed segments of the HOT lanes.

Saroj Weeraratne, PhD, PE, GE – Geotechnical Manager

Christopher Diaz, PE, GE – Geotechnical Principal

Matthew Dennerline, PE, GE – Geotechnical Project Engineer

Somadevan Niranjanan, PE, GE – Geotechnical Project Engineer

Gary K. Gilbert, PE, GE – Geotechnical Engineer (Phase II Environmental)

Our Services


  • Site and route evaluations
  • Geologic hazards
  • Seismic design
  • Site characterization
  • Subsurface drainage
  • Grading
  • Ground improvement
  • Slope stability
  • Foundations
  • Dynamic analyses
  • Pavements
  • Instrumentation


  • Material sources
  • Construction observation and testing
  • Verification of anticipated conditions
  • Evaluation of changed conditions
  • Foundation installation
  • Instrumentation
  • Claims evaluation


  • Site characterization
  • Remediation
  • Solid and liquid waste disposal
  • Landfill
  • Aerially Deposited Lead (ADL) Studies
  • Phase I Initial Site Assessments (ISA)
  • Phase II Hazardous Waste Studies
  • Sustainability


  • Forensic investigation
  • Litigation support

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