Bumper Guardian

By National Highway Traffic Safety Administration, August 2006

Table 3 Net Lifetime Benefits of Various Backup Systems On a Per Vehicle Basis ($2006, 3% discount)

It is also worth noting that one of our most sensitive variables, the percentage of low speed crashes that are backing-up crashes, is one of the unknowns for which we have the least knowledge. Our current estimate states that 10 to 25 percent of low speed crashes are backing-up crashes, but holding all other variables constant, we would need this number to increase to 50 percent, somewhere between two- to five-fold over our current estimate range, for the ultrasonic system to break even in net benefits. Similarly, another way for the ultrasonic system to break even in net benefits includes having the benefits of each crash avoided to be twice our estimated value. These sensitivity analyses show that you need large changes in our assumptions in the model to get the ultrasonic systems to break even in net benefits.

Thus, based on the assumptions and estimates in this model, which do not include any benefits for injuries or fatalities reduced, backup sensors are not cost-effective to society on a property damage basis over the lifetime of vehicles.

One perspective on this data that may not be obvious at first glance is precisely which person will pay the cost to society in these crashes. While a camera-equipped vehicle may not be very cost effective for society in certain circumstances, the driver pays for its installation, and in the event of an accident, the cost to repair will be covered partly by insurance, and partly by the other motorist if the camera was struck-in-the-rear (except in no-fault States). Therefore, it may be in the driver’s best interest to equip their car with a backup sensor to avoid backup crashes, while it may not be in society’s best interest due to increases in repair costs in those cases where the vehicle is struck in the rear.

Finally, we revisit the many questions we have considered while creating this model. The costs to repair the systems are currently extremely high, but this may be because they are considered luxury items. The effectiveness of the system is hard to pin down because of the types of property damage crashes it can affect are not well documented, as many of them take place in driveways and are not reported to police. Many assumptions were made setting up the distribution of crashes, regarding Light-Medium-Heavy damage, and the ratio of backing up crashes to struck-in-the-rear crashes.