Matthew Manjarrez, PE

Principal - Civil / Traffic Engineer, Forensic Services

Matthew is an experienced transportation professional, licensed as both a Civil Engineer and a Traffic Engineer, with over 20 years of consulting experience. Matthew serves as a technical expert in various legal matters involving vehicular, transit, bicycle, and pedestrian safety issues. Matthew has qualified and testified at trial as a highway design and traffic engineering expert in courts within the State of California. In addition, he has provided deposition testimony and written declarations in support of clients’ motions before the court.

Matthew performs technical evaluations of freeways, interchanges, local roadways, bikeways, and parking lots to determine if these transportation infrastructure elements have been reasonably and appropriately designed and operated. Matthew focuses on educating attorneys and the trier of fact in basic transportation engineering concepts to enable them to effectively evaluate, execute, and decide the case. He emphasizes the use of courtroom exhibits to clearly depict engineering concepts, findings, and data in an effective visual manner.

As both a licensed Civil Engineer and Traffic Engineer in California, Matthew executes and guides transportation engineering projects in accordance with client needs, engineering standards, and industry best practices. He possesses a unique combination of educational, professional, legal, and administrative expertise, which provides a foundation for the effective oversight of his projects. Matthew has led efforts to improve safety on transportation facilities for drivers, bicyclists, and pedestrians. His wide range of projects have spanned from Bikeway Master Plans to Traffic Signal Design to Impact Fee Programs to Environmental Impact Reports to many other areas. Matthew has developed proactive jurisdiction-wide transportation safety programs for Placer County and the City of Rocklin. Matthew strives to enhance the safety of transportation infrastructure while helping clients manage their exposure to liability.


  • Traffic Signal Railroad Preemption
  • Light Rail on Surface Streets
  • Curve Warning Signage
  • Construction Area Traffic Control
  • Parking Lot Layout & Pedestrian Accommodation
  • On-Street Parking
  • Pavement Condition
  • Access Management
  • Speed Limits
  • Design Standards & Guidelines (MUTCD, Highway Design Manual, AASHTO)
  • Traffic Engineering Implications of the California Vehicle Code


Technical areas in which Matthew has testified include:

  • Sight Distance
  • Pavement Delineation
  • Signage
  • Crosswalk Location & Warnings
  • Traffic Signal Timing & Operation
  • Pedestrian Clearance Time
  • Yellow & All-Red Time
  • Bikeway Facilities
  • School Area Traffic Control
  • Collision History
  • Median Barrier
  • Embankment Guardrail