Mary E. Ahern, P.E., - Specializes in Traffic Engineering and Traffic Signal System Design and Optimization. As an Expert Witness, Ms. Ahern has experience in determining causes of vehicle accidents, investigating pavement markings, assisting in case direction and traffic solutions, preparing sight distance calculations and accident site photography analysis. She also teaches traffic engineering and geometrics as an adjunct instructor for Northwestern University.

Areas of Expertise:Red Light Cameras

Traffic Engineering Traffic Counts Traffic Warrant Studies Traffic Signal and System Design Video Vehicle Detection Audible Pedestrian Signal Design Emergency Vehicle Preemption Design Accident Analysis

Red and Amber Clearance Interval Calculations Accident Site Photography Accident Site Video Production Sight Distance Calculations Dilemma Zone Issues Procedure Development Sales Roadway Design

Dean Tekell Consulting provides expertise in the areas of Traffic Engineering, Parking, Public Transit, Vehicle Dynamics, Accident Reconstruction, and Technical Accident Investigation.

Often, government agencies, consulting engineers, architects, developers, business institutions, and attorneys must know how to move people and their goods safely and efficiently. The firm offers advice on site selection, traffic access, and traffic circulation on the site. The firm provides insight into potential problems with zoning and subdivision regulations. Traffic impact studies, traffic signal warrant analysis, traffic signal design and permitting services related to development activity are also available through the firm. Parking garage and parking lot operations are specialties offered to business institutions.

Other services include: Queuing Studies for drive-through services; Traffic Calming and neighborhood speed control; School trip and pedestrian safety plans; Traffic Accident Reduction and highway safety techniques; Transit Funding Operation; Intelligent Vehicle-Highway Systems.

Dr. Don Donderi is a retired professor from the McGill University Psychology Department and a co-founder and Principal Consultant of Human Factors North Inc. He has a B.A. and a B.Sc. from the University of Chicago and an Experimental Psychology PhD from Cornell University. He is co-author of a psychology textbook and his research has been reported in many peer-reviewed scientific journals.

Dr. Donderi advises on the Human Factors / Ergonomics aspects of civil and criminal litigation, including Cognitive Processes, Visibility and Warnings. His research and development work is in Flight Simulation, Marine Navigation, Rail Transport, Road Transport,Air Traffic Control, Nuclear Power, and Marine Search and Rescue, including marine and aviation display design and field research in the Canadian Arctic and Atlantic Ocean.