Your car's "black box" knows how fast you're going, whether you're buckled up and if you're on the gas or the brakes.
It remembers these things for only a few seconds at a time -- until you hit something. Then, like the airplane black boxes we've read about for years, it stores the data and can spill some eye-opening secrets to safety investigators, attorneys and your car insurance company.
Called event data recorders (EDRs for short), these devices are already in many autos -- the National Highway Traffic Safety Administration said in 2008 that 65% to 90% of all vehicles had them. Virtually all new cars, the agency adds, are equipped with EDRs.
They're designed to gather information during an accident, much the same way a transponder helps aviation officials piece together why a jet goes down. The EDR is usually placed under the driver's seat and is wired to other car components, like air bags.
Starting with 2011 models, automakers are required to tell buyers that a recorder is installed in their cars. (The information usually is in the owner's manual.) And while each automaker currently builds a box that fits its own needs and standards, the NHTSA has recently decided that all vehicles built after 2013 must have standardized EDRs that record a trove of relevant, very specific details, such as:
- Change in forward crash speed.
- Maximum change in forward crash speed.
- Speed the vehicle was traveling.
- How far the accelerator pedal was pressed.
- Whether or not the brake was applied.
- Ignition cycle (number of power cycles applied to the EDR) at the time of the crash.
- Ignition cycle when the EDR data was downloaded.
- Whether or not the driver was using a safety belt.
- Whether or not the front air bag warning lamp was on.
- Number of crash events.
- Time between the first two crash events, if applicable.
- Whether or not the EDR completed recording.
Officials stress that the information is valuable when compiling federal or state accident statistics and creating safer cars and roads.
"EDRs can provide information about a crash that can't be obtained through more traditional investigation techniques," says a statement on the Insurance Institute for Highway Safety's website. "Police, crash investigators, automakers, insurance adjusters and highway safety researchers can use this information to analyze what occurred during a crash. The data may help automakers improve occupant restraint systems and vehicle structures."
But an EDR is also an unblinking eyewitness to any incident that is recorded in its memory.
