Introduction

The National Crash Analysis Center (NCAC) is a research and resource center for transportation safety studies on vehicles and highways. NCAC was established at The George Washington (GW) University--Virginia Campus in Ashburn, Va., on Oct. 1, 1992, through a contract from the U.S. Department of Transportation (DOT) and contributions from GW's School of Engineering and Applied Science. Both the Federal Highway Administration's (FHWA) Office of Safety and Traffic Operations Research & Development and the National Highway Traffic Safety Administration's (NHTSA) Office of Crashworthiness Research fund the center.

NCAC has two main goals:

• To conduct research to assist government researchers in resolving transportation safety issues.
• To combine FHWA and NHTSA crash-test films and documentation collected over the past two decades into a single national library.

The Center also provides an environment for national and international visiting scholars to conduct research using the data and facilities and to interact with the NCAC research team.

NCAC researchers use highway-use data, on-the-road crash data, vehicle crash-test data, and models of vehicles and occupants as resources. In addition, the center maintains, improves, and applies vehicle and occupant computer models developed by FHWA and NHTSA and conducts research in the development of new computer simulation models. A unique feature of the center is that researchers can combine and use all available resources.

The NCAC library provides a national resource for crash-test reports and films, current computer models used by FHWA and NHTSA, and access to accident data bases such as the Fatal Accident Reporting System (FARS), the National Accident Sampling System (NASS), and the General Estimating System. The library currently has more than 14,000 crash-test films, along with the accompanying test report (if such a report is available).

NCAC Activities and Services

NCAC houses, maintains, and makes available to the public vehicle and highway crash-test films, data, and documentation that has been compiled over past two decades by DOT. NCAC also has access to various accident reports and data bases. In addition, several computer models and software for modeling of vehicles, dummies, occupants, and highway objects are maintained and used for research at NCAC. NCAC provides an extraordinary setting in which to conduct integrated research that considers all facets of a highway transportation safety problem. Ultimately, these research findings contribute to the design of safer highways and vehicles.

The following is a summary of NCAC activities and services:

• Research on modeling and computer simulation of vehicles and roadside objects for impact analysis.
• Research on comparison of computer models and test data.
• Research on biomechanics computer simulation and analysis of human injury due to impact.
• Research on highway safety issues using crash-test films, on-the-road crash statistics, and vehicle crash-test data.
• Research, investigation, and traffic injury studies and effectiveness analyses on safety improvements.
• Validation and engineering data services for existing and new programs.
• Maintenance and improvement of available vehicle and roadside-object computer models.
• Operation, maintenance, and support for the Crash Analysis Information System (CAIS).
• Maintenance and support services for the Crash Test Information System (CTIS).
• Response to user inquiries on computer programs.
• Response to user inquiries on crash-film resources.
• Development and support of the International Visiting Scholars Program.

Vehicle and Highway Safety Research

The main goal of NCAC is to use its available resources to resolve transportation safety issues. FHWA's Office of Safety and Traffic Operations Research & Development is primarily concerned with the crash analysis and testing for highway design safety and roadside objects, NHTSA's Office of Crashworthiness Research focuses on regulations for safer vehicles and occupant protection.

Research at NCAC focuses on both aspects of the safety problem and combines the findings from both roadside objects and vehicle/occupant analyses. Research at NCAC starts with reviewing the accident data from various data bases and statistical analyses of injury patterns, frequencies, and severity to identify and characterize the impact problems for further investigation. The specific problems, tasks, and objectives are defined jointly with FHWA and NHTSA.

The research philosophy at NCAC is to look at the overall safety issue, use the available resources to identify and characterize the problem, use the most appropriate methods and tools or a combination of them to analyze the problem, and ultimately, recommend solutions or approaches that will enhance the safety of occupants and reduce harm. Another aspect of the research at NCAC is to evaluate the current methods of transportation safety analysis and make improvements as research progresses, rather than relying on the existing tools.

The research activities at NCAC are divided into two major groups under two directors working with the principal investigator: (1) simulation and modeling research and (2) biomechanics and safety research. A basic theme for research is selected after the actual accident and test data are reviewed and several tasks are identified under that theme. The two research wings of the center then join forces and closely coordinate their work to solve the problem. Identification and sufficient characterization of the problem from accident records and statistical data analysis concerning various crash frequencies and severity and occupant casualties are a major part of the research activities.

Another major area of concentration in safety research at NCAC is the application, development, and enhancement of simulation tools and methods. Special-purpose simulation programs, rigid-body dynamics programs, and finite element structural codes are developed or use to model various aspects of vehicle crashes. These include modeling vehicle and occupant motion, vehicle-roadside object impact, dynamic and impact response of various highway objects, vehicle components, restraint systems, dummies, occupants, and biomechanics simulation. Finite element and multibody dynamics programs used extensively by the research team include DYNA3D, NIKE3D, PATRAN, HVOSM, GUARD, NARD, among others.

Recent Research Theme

The currently identified research theme is "analysis of vehicle impacts with narrow objects." Efforts are expanded in:

• Data base analysis and identification.
• Analysis of safety issues (e.g., intrusions, types of bodily injury).
• Modeling, simulation, validation, and evaluation.

Currently, the simulation research at NCAC is concentrated on finite element modeling. The codes primarily used for this purpose are DYNA3D and NIKE3D software. DYNA3D is a nonlinear, explicit dynamics finite element analysis code suited for high-impact rate and large deformation problems. DYNA3D is widely used by researchers in the field, the automobile industry, and both FHWA and NHTSA to model vehicle impact problems. NIKE3D is an implicit finite element code with similar characteristics. Both the public domain and commercial versions of these codes are currently undergoing further improvement.

Research Topics

NCAC is currently conducting research concerning:

• Finite element analysis and evaluation of the performance of 4-lb/ft, U-post channel sign support using crash-test data.
• Cost/benefit analysis on testing and simulation of vehicles and roadside objects.
• Three-dimensional finite element modeling of the human surrogate head using DYNA3D.
• Modeling of lower limb injuries in vehicle crashes: human ankle and foot.
• Research on development of general protocols for finite element interfaces and pre- and post-processing.
• Analysis of injury patterns and severity in support of Jackson Memorial Hospital's Ryder Trauma Center.
• Statistical data analysis of recent field accident records concerning crash frequency and severity and also occupant casualties in the collision of vehicles with narrow objects.

NCAC Film Library Services

The NCAC film library includes the collections of FHWA's Roadside Safety Library (RSL), NHTSA's New Vehicle Assessment Program (TRD/Docket), Office of Crashworthiness Research (OCR), and the compliance films. Furthermore, accident study data files from several hospitals, including Jackson Memorial's Ryder Trauma Center and Children's Hospital, are maintained by the NCAC library. The reports of several DOT committees on safety research will also be cataloged and shelved in the NCAC library.

Several specialized simulation software developed during the past two decades by DOT, including NARD, GUARD, HVOSM, GRAPHx, BARRIERIV, and PORCHE, are maintained at the NCAC library.

These resources are available to NCAC's scientists, DOT researchers and engineers, and the public. The NCAC library provides these resources to the public under certain rules and government-approved cost schedules.

NCAC also provides services for public viewing of crash-test films on VCRs and 16-mm film projectors, reviewing of printed crash-test reports and documents on paper and microfiche, and viewing of test pictures and slides. A public viewing and projection room equipped with the necessary audiovisual equipment is dedicated to these services. Arrangements to use these facilities may be made by contacting the NCAC library. During regular business hours, visits to the NCAC library can be arranged by appointment or walk-in.

GW-Virginia Campus

GW-Virginia Campus provides an ideal setting for this unique center. Dedicated to the study of advanced technology and management techniques, this campus is located near Washington, D.C., eight kilometers (five miles) north of Dulles International Airport in one of America's most dynamic high-tech regions. GW's Virginia Campus reflects both the university's rich tradition and its bold future in graduate engineering education and research. GW's School of Engineering and Applied Science currently houses several high-caliber research laboratories at the Virginia Campus and offers 11 masters and doctoral programs, including one in transportation safety that will commence in fall 1994. The transportation safety program is offered by the Civil, Mechanical, and Environmental Engineering (CMEE) Department and cover a range of courses in mathematics, systems modeling and simulation, solid mechanics, biomechanics, structural dynamics, and so forth. This program provides a solid background that enables students to pursue their scholarly research in the transportation field. It is expected that state and federal highway safety engineers, accident investigation and insurance institute engineers, and investigators in the field of forensic engineering, among others, will be candidates for graduate study in this program. Graduate students will interact with GW's faculty and use the resources available at NCAC.

The main goal of NCAC is to use its available resources to resolve transportation safety issues.

Dr. Azim Eskandarian is an associate research professor at GW-Virginia Campus, and he is the director of simulation and modeling research at NCAC.

Dr. Nabih E. Bedewi is the director and principal investigator of NCAC.

Leonard Meczkowski is a highway safety specialist in FHWA's Office of Safety and Traffic Operations Research and Development. He is FHWA's contracting officer's technical representative (COTR) assigned to oversee the operations of the NCAC.