John Zolock

John Zolock, PhD, PE, ACTAR is a Principal Engineer in the Vehicle Engineering Practice, specializing in ground transportation crash analysis and reconstruction, vehicle crashworthiness and occupant protection, and the analytical and experimental evaluation of physical dynamic systems. 

Expertise in Accident Reconstruction

Dr. Zolock has participated in more than 1,000 engineering- and scientific-based accident reconstruction matters across a diverse range of ground transportation modes. This work encompasses incidents involving automobiles; buses (transit, coach, shuttle, school); pedestrians; medium and heavy trucks (straight trucks, tractor-semitrailers, and vocational trucks); motorcycles (on-road, dirt bike, scooter, three‑wheel); go-karts; bicycles; golf carts; off-highway recreational vehicles; heavy equipment; construction equipment; and rail vehicles (passenger, locomotive, freight, subway).

He has specialized expertise in analyzing factors that may contribute to and/or cause ground transportation accidents, such as roadway conditions; line-of-sight; vehicle speed and stopping distance; the performance and function of vehicle components and systems; right-of-way violations and centerline encroachments; vehicle handling characteristics; and collision avoidance and Advanced Driver Assistance Systems (ADAS) technology.

Specialized Technical Expertise

Dr. Zolock's extensive experience spans advanced methodologies and testing protocols, enhancing his consulting contributions to accident reconstruction. Dr. Zolock's work integrates material science, applied mechanics, dynamics, vibrations, Finite Element Analysis (FEA), biomechanics, and human injury testing using Anthropomorphic Test Devices (ATDs). His experience spans photogrammetry, passenger vehicle and heavy truck event data recorder (EDR) download and analysis, dynamic system testing, dynamic system simulation, full scale rail vehicle testing, along with physical testing and evaluation of the design and performance of Roll Over Protection Structures (ROPS) for off-highway recreational vehicles. Dr. Zolock also has expertise in automobile full-scale crash testing, dolly rollover testing, handling testing, sled testing, and regulatory compliance testing (relative to Federal Motor Vehicle Safety Standards) which enhances his consulting contributions to the reconstruction of accidents.

Dr. Zolock regularly utilizes the latest software and hardware tools to collect, synthesize, and interpret the electronic data, videos, and images stored in vehicles and equipment. This includes imaging data from event data recorders (EDR), electronic control modules (ECMs), engine control modules, brake control modules, airbag control modules (ACM), advanced driver assistance systems (ADAS), and telematics systems including Geotab, Lytx, Omnitracs, PeopleNet, Samsara, and Tesla.

Using photogrammetry - a scientific method for obtaining precise and reliable measurements of objects and features captured in photographs and video — has been a cornerstone of Dr. Zolock's engineering work. He has been utilizing photogrammetry in its various forms for more than 25 years and on hundreds of different circumstances. These include ground-based and close-range photogrammetry methods such as image rectification, camera-matching, and reverse projection applied to still images, stationary and moving videos, and secondary recordings of a video playback (video-of-a-video).

For more than 20 years Dr. Zolock use been using human modeling with the MAthematical DYnamic MOdels (MADYMO) simulation software to analyze complex human motion scenarios such as vehicle-to-vehicle collisions, vehicle-to-pedestrian collisions, vehicle-to-bicycle collisions, vehicle-to-motorcycle collisions, human motion during vehicle rollovers, impacts from moving equipment, impacts from flying or falling objects, humans falling from height, humans falling over railings, humans falling from vehicles, humans falling into openings, and humans sitting onto furniture. Additionally, Dr. Zolock has also used MADYMO when working with consumer and industrial products companies to evaluate the safety of products, prototypes, and experimental transportation systems. Dr. Zolock has conducted research programs that have explored the validity of the MADYMO simulation-based tool for human modeling.

Vehicle Rollovers

Dr. Zolock has specialized expertise developed through extensive work on hundreds of vehicle rollover accidents. In this area, he has contributed to the rollover accident community by conducting multiple sophisticated research studies that employed various rollover methodologies, advancing the understanding of vehicle and occupant kinematics and dynamics in real-world rollover crashes.

Vehicle Research and Testing

Dr. Zolock has conducted research and testing involving rail vehicles, passenger cars, trucks, and pedestrians. The testing has been utilized to validate reconstructions, understand vehicle and occupant kinematics and dynamics, assess restraint system performance, and research the performance of occupant protection systems in the context of the crashworthiness of vehicle structures. As a result of this work, Dr. Zolock is highly knowledgeable in the configurations and measurements obtained by the Anthropomorphic Test Devices (ATDs, test dummies) used in crash and rollover testing, and how that testing relates to simulation utilizing MADYMO and relevant Injury Assessment Reference Values (IARVs).

Regulatory and Standards

Dr. Zolock is well-versed in state and federal safety standards and consumer information ratings associated with vehicle performance in static and dynamic testing. Dr. Zolock has evaluated vehicles with respect to National Highway Traffic Safety Administration (NHTSA) FMVSS Regulations, Federal Railroad Administration Regulations (FRA), American Public Transportation Association (APTA) recommended practices, and the ANSI/ROHVA standards. Dr. Zolock has developed specialized expertise in designing and conducting vehicle crash and sled tests, handling tests, automotive component testing, and restraint system evaluations that relate to a specific accident or relevant regulations. Dr. Zolock has conducted physical testing and evaluated the design and performance of Roll Over Protection Structures (ROPS) for off-highway recreational vehicles, as well as evaluated the kinematics and dynamics of these recreational vehicles.

Motorcycle

Dr. Zolock is an experienced motorcycle operator with specialized expertise in motorcycle accident reconstruction and handling dynamics. He rides regularly and has completed both classroom and hands-on riding skills training in on-road, off-road (dirt bike), and three-wheel motorcycle operation.

Professional Background

Prior to joining Exponent, Dr. Zolock served nine years as a Mechanical Engineer at the U.S. Department of Transportation's Volpe National Transportation Systems Center in Cambridge, Massachusetts. His work focused on research and development projects addressing railroad vehicle-track interaction, train-derailment causation and prevention, train make-up and performance, rail vehicle suspension design and performance, rail vehicle crashworthiness, accident injury causation, and occupant safety and protection for rail vehicles.

Academic Contributions

While working at the Volpe Center, Dr. Zolock wrote a Ph.D. dissertation at Tufts University titled, "A Methodology for the Modeling of Forced Dynamical Systems from Time Series Measurements using Time-Delay Neural Networks." The dissertation studied the use of artificial intelligence (neural networks) to predict the wheel/rail force response of rail vehicles to track geometry variation.

While at Penn State University, Dr. Zolock wrote a thesis titled, "Experimental Observation and Characterization of Tire Standing Waves." At Penn State, Dr. Zolock's curriculum focused on experimental and analytical dynamics, vibrations, modal analysis, signal analysis, mechanics of materials, and composite materials. Previous work experience at Micro Motion included experimental and analytical modal analysis of Coriolis-based mass flow meters and high-pressure feed-through testing and design.

Education and Credentials

Dr. Zolock's formal educational background includes a Bachelor of Science degree in Mechanical Engineering from Grove City College, a Master of Science degree in Engineering Science and Mechanics from the Pennsylvania State University, and a Doctoral degree in Mechanical Engineering from Tufts University. Dr. Zolock is a registered professional mechanical engineer in six states, including Connecticut, Massachusetts, Michigan, New York, Pennsylvania, and Rhode Island. Dr. Zolock is a certified traffic accident reconstructionist by the Accreditation Commission for Traffic Accident Reconstruction (#2550).