SP-1: Wheelchair Accidents Investigation

Investigation of the Incidence, Extent, and Nature of Injuries to Wheelchair-Seated Riders Due to Motor-Vehicle Accidents

Importance of the problem

Description of the need and target population

It has been estimated that there are approximately 1,700,000 non-institutionalized adults and children in the United States who use wheelchairs for their primary means of mobility on a daily basis (Kaye, 2000). Although this constitutes a relatively small percentage of the total U.S. population, the number of wheelchair users has been increasing steadily for many years, and will no doubt continue to increase in the years and decades ahead. At the same time, this is a population of people who are increasingly active and integrated into the mainstream of society, which, in today's world, means that these are people who use various means of motor-vehicle transportation on a daily basis.

In the past 25 years, two public laws have helped to enhance the active lifestyles of wheelchair users. For school-aged wheelchair users, the Individuals with Disability Education Act (IDEA), formerly known (1976) as the Education for All Handicapped Act, requires that children with disabilities be transported to and from school. Similarly, the Americans with Disability Act (ADA) requires that all public transportation systems, including public transit motor vehicles, provide for transporting persons with disabilities, including persons who use wheelchairs for personal mobility. However, for many years, these federal laws dealt primarily, or exclusively, with allowing wheelchair users to access and travel in motor vehicles, and did little or nothing to ensure that people seated in wheelchair were being provided with a safe ride.

In the past ten years, the issue of safe transportation for wheelchair-seated occupants of motor vehicles has been partially addressed through enhancements to Federal Motor Vehicle Safety Standard (FMVSS) 222, School Bus Passenger Seating and Crash Protection, and through the development of a Society of Automotive Engineers (SAE) Recommended Practice J2249, Wheelchair Tiedown and Occupant Restraint Systems for Use in Motor Vehicles (SAE, 1996) and ANSI/RESNA WC/19, Wheelchairs Used as Seats in Motor Vehicles (ANSI/RESNA, 2000). These latter documents specify design and performance requirements for wheelchair tiedown and occupant restraint systems (WTORS) and for wheelchairs intended for occupancy in a motor vehicle (i.e., transit wheelchairs).

Also, in recent years, there have been at least four federally funded programs aimed at further specifying and improving wheelchair tiedown and related occupant restraint systems. These include Federal Transit Authority (FTA) funding of separate studies at the Cleveland Clinic and Oregon State University (Hunter-Zaworski, 1992 a &b) through Project Action to develop docking-type tiedown systems for wheelchair securement in public transit, a third project funded at ECRI (1994) through Project Action to evaluate procedures and practices for positioning and securement of wheelchair-seated occupants, and, most recently, a project funded at the Cleveland Clinic by the Transit Cooperative Research Program (TCRP) of FTA to develop new guidelines for evaluating wheelchair tiedowns and occupant restraints used in the transit and paratransit environments.

To date, the provisions of the voluntary standards and practices related to safe transportation of people in wheelchairs are based on very fundamental principles of occupant protection in frontal motor-vehicle crashes; namely that effective occupant protection in a frontal crash requires effective occupant restraint, which, in turn requires effective and secure occupant seating. They are also based on the assumption that persons in wheelchairs are subjected to the same levels of risk exposure as able-bodied travelers. Since the focus of standards development efforts have been on the equipment used by wheelchair-seated occupants (i.e., their seat or wheelchair, the wheelchair securement system, and the occupant restraint), the standards development efforts to date have established dynamic strength performance requirements based on "worst-case" loading scenarios. For the wheelchair user, involved in a frontal crash, this implies a 30-mph crash delta V, similar to that used for child safety seat testing of FMVSS 213, and similar to the barrier impact speed required by FMVSS 208 Frontal Crash Protection.

While this has been a reasonable approach for standards dealing with after-market products that are installed or used in a wide range of vehicle types and sizes, which is generally the situation for many WTORS and transit wheelchairs, the requirements of these standards are probably too high for many sizes of vehicles and types of transportation services, where a 30-mph frontal crash is an extremely unlikely event. In these situations, a much lower level of dynamic strength testing would be appropriate, and would allow for different approaches to wheelchair securement and occupant restraint that are more compatible with other constraints and demands of public transportation systems. It is also likely that the needs of the wheelchair-seated occupant, with regard to transportation safety, are different than for most able-bodied individuals, and that wheelchair-seated occupants may be more susceptible to severe and fatal injuries in circumstances that would not be injurious to able-bodied travelers.

In order to proceed with research and development activities, and establishing reasonable and appropriate standards and policies for safe transportation of wheelchair-seated occupants in all types of vehicles and modes of transportation, and in order for public transit providers to make reasonable informed decisions involving tradeoffs between equipment and procedures used for occupant restraint of wheelchair riders and effectiveness of vehicle operation and service, it is important to have a better understanding of the real-world experience of wheelchair users with regard to injuries sustained in motor-vehicle crashes and other non-impact vehicle events. Unfortunately, standard crash/injury databases that are commonly used to determine incidence, extent, and patterns of injury for different crash modes and different vehicle types do not provide information about whether an occupant was seated in a wheelchair. Thus, these traditional sources of crash and injury data, such as the National Automotive Sampling System (NASS) and the Fatal Accident Reporting System (FARS) cannot be used to determine even anecdotal information on injuries to wheelchair users. Furthermore, these databases do not include information on crashes and injuries of public vehicles, such as school and transit buses, which are common modes of transportation for many wheelchair users.

Beneficial impact on target constituency, including service providers

The results of the tasks in this priority will provide a clearer understanding of the extent and nature of injuries to wheelchair-seated occupants of different types of vehicle and transportation services. This information will help to understand the levels of risk of wheelchair travelers in different vehicle/transportation environments and the unique factors that may contribute to wheelchair occupant injuries compared to able-bodied travelers. It will, therefore, provide input to setting priorities and criteria for further research and development efforts, as well as to the development and modification of standards and recommended practices related to providing safer transportation to wheelchair-seated passengers and drivers. Finally, public and school transportation professionals and service providers can use the information in making decisions that involve tradeoffs between occupant safety and effectiveness of transportation systems and service delivery. The end beneficiaries will be individuals who must travel while seated in a wheelchair, who will do so with increased safety and operational efficiency.

Responsiveness to priority

The three tasks in this priority are in direct response to the NIDRR-announced priority (a), Investigate and report on the incidence, extent, and nature of injury of wheelchair riders due to motor-vehicle accidents, making a distinction between the cause of accident, the cause of injury, the type of vehicle or transportation service involved, and the vehicle size and weight, and include recommendations for ways to minimize injuries.

Overall objectives

The specific aims of the tasks of this priority are to obtain, compile, analyze, and disseminate data and information on the following:

  1. incidence, extent, and nature of injuries to wheelchair riders due to motor-vehicle accidents, in different types of vehicles and in different types of transportation services,
  2. relative levels of risk of wheelchair-seated occupants in different types and sizes of vehicles and types of transportation services, and in comparison to able-bodied travelers,
  3. types, frequencies, and severities of motor vehicle crashes and other moving-vehicle events that result in injuries to wheelchair-seated occupants,
  4. differences between injury risk and causation scenarios between wheelchair-seated travelers and able-bodied travelers for similar conditions of vehicle size and transportation services,
  5. real-world crash performance of wheelchairs, wheelchair tiedowns, and wheelchair occupant restraints that comply with existing and future standards.

In addition, the tasks of this priority will improve the quality and quantity of available data on accidents and injuries to wheelchair-seated occupants of motor vehicles in the future. This will be accomplished through improvements in procedures for coding the presence of an occupied wheelchair in motor-vehicle crashes, and by improving the methods for describing wheelchair securement and wheelchair-user restraints in federally funded crash-investigation programs.

Organization of work plan

Due to the lack of crash and injury data available for wheelchair-seated occupants of motor vehicles, obtaining information and analyzing data for levels of injury risk and patterns of injury to people seated in wheelchair when involved in a motor-vehicle crash or other injury-producing event, cannot be easily done. It is for this reason, that a three-pronged approach to gathering this important information is proposed. This project is organized into the following three interrelated tasks phased over the 60-month period of the RERC program:

  1. SP-1a: Transportation Safety Survey of Wheelchair Users
  2. SP-1b: In-Depth Investigations of Injuries to Wheelchair-Seated Drivers and Passengers in Motor-Vehicle Crashes and Non-Impact Vehicle Maneuvers
  3. SP-1c: Investigation of the Frequency, Severity, and Nature of Bus Accidents, with Comparison of Injuries to Wheelchair-Seated and Able-Bodied Occupants

The priority will be lead by Dr. Lawrence Schneider, who will also lead Task SP-1b Accident/Incident Investigations. Tasks SP-1a and SP-1c will be lead by Dr. Tom Songer and Dr. Greg Shaw, respectively. Task SP-1c will take place in the first 24 months, while Task SP-1a will take place in the first 36 months. Task SP-1b will begin in Year 1 with the establishment of an accident/incident notification network and with the development of data elements that are unique to wheelchair-seated occupants, but most of the investigations will take place in Years 2 through 5.


ANSI/RESNA, Volume 1: Requirements and Test Methods for Wheelchairs; Section 19: Wheelchairs Used as Seats in Motor Vehicles. RESNA Secretariat, Arlington Virginia, Approved May 2000.

ECRI. Positioning and securing riders with disabilities and their mobility aids in transit vehicles; designing an evaluation program. Project Action, Washington, DC, 1994.

FMVSS 208 - National Highway Traffic Safety Administration, Department of Transportation Code of Federal Regulations, 49 CFR 571.208, Standard No. 208: Occupant Crash Protection (10-1-00 Edition), pp. 480-554. U.S. Government Printing Office, Washington, D.C.

FMVSS 213 - National Highway Traffic Safety Administration, Department of Transportation Code of Federal Regulations, 49 CFR 571.213, Standard No. 213: Child Restraint Systems (10-1-00 Edition), pp. 578-614.. U.S. Government Printing office, Washington, D.C.

FMVSS 222 - National Highway Traffic Safety Administration, Department of Transportation. Code of Federal Regulations, 49 CFR 571.222, Standard No. 222: School Bus Passenger Seating and Crash Protection (10-1-00 Edition), pp. 670-681. U.S. Government Printing Office, Washington, D.C.

Hunter-Zaworski, KM, Ullman, DG, Herling, DE. Application of the Quality Functional Deployment Method in Mobility Aid Securement System Design: Vol. 1. Federal Transit Administration, Washington, DC, Report No. FTA-OR-11-0006-92-, Dec 1992a.

Hunter-Zaworski, KM, Zaworski, JR, Clarke, G. The Development of an Independent Locking Securement System for Mobility Aids on Public Transportation Vehicles: Vol. 2. Federal Transit Administration, Washington, DC, Report No. FTA-OR-11-0006-92-2,Dec 1992b.

Kaye, HS, Kang, T, LaPlante, MP. Disability Statistics Report – Mobility Device Use in the United States. Washington, DC: US Dept of Education, National Institute of Disability and Rehabilitation Research, June 2000.

SAE Recommended Practice J2249 Wheelchair Tiedowns and Occupant Restraints for Use in Motor Vehicles SAE International, Warrendale, PA October 1996.

Last updated: April 11, 2002