Pros and cons of EDRs

One way of keeping track of someone's driving habits is with an Event Data Recorder. EDRs, also called "Black Boxes," are best known for helping investigators reconstruct airplane crashes by preserving logged information from the cockpit before a crash. But EDRs have also been on the highways for years. Car manufacturers first started installing them as a way to track air-bag effectiveness. Aftermarket devices came next, initially used by fleet managers to keep tabs on commercial drivers. Capable of recording many dangerous or aggressive driving habits, EDRs are now being marketed to parents concerned for their children's safety.

In addition to keeping a record of a driver's behavior, the two aftermarket EDRs we tested can provide an audible warning to drivers if the device senses hard acceleration, braking, cornering, or speeds in excess of a preset limit. The alarm can serve as a teaching aid, reminding the young driver or alerting an adult instructor. The sound can also be disabled to prevent a driver from knowing their behavior is being monitored. Recorded trip information can be downloaded to a home computer, giving parents an opportunity to review the information with young drivers.

With the increased use of EDRs in passenger vehicles, there has been concern about privacy issues—particularly since so many buyers are unaware their vehicles are equipped with them. Court cases on motor vehicle accidents have been decided based on evidence captured by EDRs, sometimes without the defendant knowing their vehicle was equipped from the factory with such a device.

Consumers Union is concerned about these and other privacy issues. In 2004 the organization issued a statement saying in part, "Consumers Union has been actively involved in efforts to secure greater privacy rights for consumers and to protect data that consumers themselves should control from getting into other hands without their consent."

We also believe the information provided by EDRs could be a boon to the development of both safer vehicles and roads when fairly managed and properly protected. To that end, we performed our test to see how effective aftermarket EDRs would be as tools to help parents monitor and teach safe driving. While the two units we tested are marketed largely for the same purpose and perform similar functions, they have significant differences in features, size, and price.  

How we tested

We evaluated each model in three categories: features, ease of use, and performance. Tests were conducted in everyday driving on public roads and in controlled conditions at our auto test center. At the track, we compared speed and acceleration numbers from the devices against our auto-test measuring equipment.