Recovering the Information Stored in the Automobile's “Black Box”
The Event Data Recorder (EDR), commonly known as the “black box”, is typically part of an Airbag Control Module (ACM), located in the passenger compartment of an automobile. The EDR records information about the airbag system and other crash related data. Data is recorded after an airbag deployment and/or near-deployment event. Recorded information can vary, but usually consists of information about a vehicle’s change in speed (delta-v), pre-impact speed, pre-impact braking, seat belt usage, and throttle position.
Since the early 90’s, vehicle manufacturers have equipped their vehicles with Airbag Control Modules (ACM) capable of recording information during an accident. The ACM measures the severity of a crash and determines whether or not to deploy safety devices like airbags and seat belt pretensioners. After signaling any safety device, information about the vehicle at the time of an event can then record data in the Event Data Recorder (EDR). This information can be imaged with the Bosch Crash Data Retrieval Tool and be used as evidence in a reconstruction.
The CDR Tool can currently image information from many automotive manufacturers including, but not limited to, GM, Ford, Chrysler, Toyota, Honda, Nissan, and more. Please visit the CDR System website for a complete Crash Data Retrieval Vehicle Coverage list.
What Data Will Be Recorded?
Depending on the vehicle, some or all of the following data will be recorded and will be able to be downloaded:
- Pre-impact vehicle speed
- Pre-impact brake status
- Delta-V vs. time for frontal airbag deployment event
- Engine speed
- Ignition cycle count at event time
- Ignition cycle count at investigation
- Maximum Delta-V for near-deployment event
- Passenger’s airbag state (enabled/disabled)
- SIR Warning Lamp status (or/off)
- State of driver’s seat belt switch (on/off)
- Throttle position
- Time between near-deploy and deploy event
- Time from vehicle impact to airbag deployment
- Time from vehicle impact to time of maximum Delta-V
Uses for the Information
There are many potential uses for this information such as:
- Assists traffic accident reconstructionists in their accuracy, reliability and understanding of a particular accident.
- Validates crash reconstruction programs
- Improve Vehicle Design/Highway Infrastructure
- Provide a Basis for Regulatory and Consumer Information Initiative
- Provide Objective Data for Crash Reconstruction
- Develop an Objective Driver Behavior Database
In accident reconstruction, this information will assist the reconstructionist with the following information:
Pre Crash Data
Gives seconds of pre-crash data such as vehicle speed, engine speed, braking and percent throttle.
Data Summary – Vehicle system status, warning lamp, drivers seat belt switch and pre-impact data.