This report responds to congressional interest and requirements to examine the safety problem of motor vehicle backover crashes involving pedestrians and the evaluation of available technologies that might help to reduce them.  Special interest was expressed regarding the involvement of small children in these types of crashes.

The size of the safety problem can only be roughly estimated because many of the backover crashes that occur on private property are not recorded in State or Federal crash databases, which focus on crashes occurring in traffic-ways.   Supplementing NHTSA crash records with death certificate reports, backover crashes involving all vehicle types are estimated to cause at least 183 fatalities annually.   In addition, between 6,700 and 7,419 injuries result from backover crashes per year.   A significant portion of these injuries are minor.

NHTSA tested several systems currently available as original equipment on vehicles and aftermarket products to evaluate their performance and potential effectiveness in mitigating backover crashes.   The backover prevention technologies that are currently offered by vehicle manufacturers are marketed as“parking aids,” which are designed to assist attentive drivers in performing low speed parking maneuvers.   Some aftermarket systems using similar technologies are being marketed as safety devices.

Testing showed that the performance of sensor-based (ultrasonic and radar) parking aids in detecting child pedestrians behind the vehicle was typically poor, sporadic and limited in range.   Based on calculations of the distance required to stop from a typical backing speed, detection ranges exhibited by the systems tested were not sufficient to prevent collisions with pedestrians or other objects.   

Of the technologies tested for their potential to reduce backover incidents, the camera based systems may have the greatest potential to provide drivers with reliable assistance in identifying people in the path of the vehicle when backing.

However, the Agency cautions readers of this report about relying on the results of our testing or other published test results to promote such systems as an effective means to address the backover crash risk.  In order to reduce the number of backover incidents, it is very important to obtain a better understanding of the environmental factors that limit the camera’s effectiveness and the limits of driver performance using such systems.

One particular concern is that camera performance can change from vehicle to vehicle and from situation to situation.  For example, rain, fog or other inclement weather can significantly reduce their ability to show drivers a clear view of objects in the danger zone in back of the vehicle.  Even in clear daytime conditions, objects in the camera display may be difficult to see due to sun glare.  A fuller understanding of these limitations is needed.

Further, the ability of drivers to become accustomed to such systems and then to use them effectively when backing needs to be better understood.  Even if cameras allow the driver to identify an object in the back of a vehicle, the driver must look at the display and have the capability to identify an object or person in the path when backing up, and to react and brake quickly enough to prevent the incident.  The speed being traveled, the level of driver attention and reaction time all play significant roles in estimating the systems’ effectiveness.

Because of the potential that camera-based systems appear to offer in addressing the risk of backover, NHTSA plans to conduct additional work to estimate the effectiveness of such systems and to develop specifications of performance for any technology that could be developed to address this risk.  Further, the Agency plans to encourage vehicle manufacturers to continue to develop systems that can be effective in addressing this risk at a reasonable cost to the consumer.

Future Research Plans

Because of NHTSA’s  concern about the serious safety problem presented by vehicle backing crashes, the agency intends to continue its work to address this hazard by conducting research in analyzing the safety problem more thoroughly and understanding the various scenarios under which such crashes occur.  Additionally, the research will be aimed at technology-based countermeasures to make them more effective.  These research activities are listed as either ongoing activities or those that are planned for the future.

Ongoing Research Activities

• Obtain more detailed information of the circumstances of the backover incidents and to provide accurate annual estimates of the number of deaths and injuries resulting from these crashes.
• The AAA Foundation is surveying thousands of AAA members who have purchased vehicles equipped with these technologies.  NHTSA will be analyzing their responses to learn about the potential benefits and problems drivers are experiencing.
• Provide information to consumers regarding the hazard due to backover incidents and resulting injuries.

New Planned Activities

• Conduct additional research to estimate the potential effectiveness of camera-based systems.
• Develop in consultation with the industry and others, specifications for the performance of systems intended to prevent backover crashes.
• Sponsor meetings and discussions with stakeholders to share research findings, identify advances in technology and identify additional research needs relating to backover.
• Encourage the industry to continue research and development of vehicle-based systems that can address the backover hazard.

(Please see the associated PDF document for the full report)