Do all passenger vehicles have an EDR unit?

Any vehicle with an airbag control module may have an EDR function, but at this time, only select General Motors and Ford manufactured vehicles have EDR units that permit data access and harvest by the public. While many more manufacturers have plans for public accessibility in the years to come, under a new federal law finalized in August of 2006, by the year 2011 (and most by 2010), all passenger vehicles sold in the United States that have an EDR function will be mandated to make the data recorded on their EDR units accessible to the public. Currently about one third of the vehicles on US highways today, have publicly retrievable EDR data.

When will the EDR unit record data?

For most late model vehicles, data is recorded beginning about 5 to 25 seconds prior to an event or impact that causes the vehicle to experience a change of velocity that exceeds a threshold significant enough to alert the airbag module of the vehicle.

What data is recorded on the EDR unit?

At this time the data that is recorded varies depending on the vehicle manufacturer, make, model and model year. In general it may record data elements like vehicle speed, engine speed (in RPMs), percent throttle, braking status, longitudinal or forward post crash velocity changes, and seat belt usage. By 2011, all vehicles being sold in the United States that collect EDR data, (most models by 2010) will be mandated under federal law to have EDR units that are available for public retrieval, and that are mandated to record a minimum of 15 data elements specified under the law, including those stated above, in events detected by the airbag module, under a standard event detection threshold.

Do all vehicles record the same data every time?

No. In addition to the data collection capability variations between vehicles, some older EDRs may collect different data depending on whether the airbag deploys or not. In addition, the data recorded may depend on whether the vehicle has sufficient time to store the data. If the impact is so severe that it severs the communication to the airbag module before it has the opportunity to store the data, a partial recording of data may result. In very rare instances, the location of the impact can destroy the EDR unit itself in which case no data can be retrieved.

How long is the recorded data saved on the EDR unit?

Data recorded following an airbag deployment is permanently stored on the EDR unit. Data recorded on GM vehicles following a non-deployment event is stored for 250 ignition cycles (i.e. turning the vehicle on and off equals one ignition cycle) or until a non-deployment event of greater magnitude (i.e., a higher change of velocity) is detected.

Does the EDR unit record video or sound?

No. Original manufacturer installed EDR units record the operational aspects of the vehicle (what is in operation) for approximately five to twenty five seconds prior to impact. They do not record any sound nor do they collect any video.

What triggers the recording of data on the EDR unit?

The recording is triggered by the detection of an "event" which is an impact that exceeds a minimum threshold for change of velocity (typically 5 mph or less depending on the vehicle).

Is it possible for a passenger vehicle to be involved in a collision and not have any data recorded on the EDR unit?

If the impact does not exceed the minimum threshold for change of velocity, then it is possible that no data will be recorded, although data can be recorded even if the airbag does not deploy.

Does the EDR unit continuously record data?

The EDR continuously monitors the speed, braking, throttle, etc. but does not store a record of the data unless there is an event that awakens the airbag module. For GM vehicles, the data is typically stored for 5 seconds prior to the event. For Ford vehicles, the data can be stored up to 25 seconds prior to the event. Ford "pre-crash" data will typically only be available if the airbag deploys and the pre-crash data is locked.

Does the EDR unit record where the vehicle has traveled or the driving habits of the driver?

No. The EDR technology does not include GPS capability and only stores a record of information about an event if the event involves a change of velocity that exceeds the minimum threshold for detection around the time of the event.

Will the EDR unit record data if the airbag does not deploy?

If the minimum threshold for change of velocity is exceeded, the vehicle can store a record of the data surrounding the event.

Can the data recorded on an EDR unit be tampered with?

The EDR data is highly resistant to tampering and includes safeguards to indicate if the EDR data has been altered once it has been retrieved from the vehicle.

Will the EDR data tell me who was at fault in an accident?

The data itself will not generally indicate fault. The use of the data in combination with other evidence, such as physical evidence at the scene, accident reconstruction and various other information will assist in determining what happened, and hence, who was at fault. Because the data is completely unbiased, reliable and objective, it can be extremely helpful in ultimately determining the cause, and possibly fault in the accident.

Can EDR data be used at trial?

While EDR data is somewhat new to the legal industry, so far it has enjoyed tremendous success in being admitted into evidence and being effective in determining what happened in an accident. See EDR Legal Updates on Case Law for more specific information regarding cases that successfully utilized such data in the courtroom.