Automobile Accident Reconstruction:The “Black Box” John K.PowersPowers & Santola, LLP39 North Pearl StreetAlbany, New York 12207(518) firstname.lastname@example.org
Driver Seat Belt Sensor Brake ON/OFF Sensor Vehicle Speed Sensor Engine Speed Sensor Throttle Pos Sensor 1999 EDR Simplified Block Diagram Pre-impact data Serial data bus SDM Accelerometer Warning Indicator Low-pass Filter Airbags Power • Microcomputer Including EDR • RAM • 32k ROM • 640 EEPROM Ignition Switch Manual Pass. Airbag Cutoff Sw. And Indicator
GM Systems Data Stored 1990 DERM 1994 SDM 1999 SDM Parameter State of Warning Indicator when event occurred (ON/OFF) Length of time the warning lamp was illuminated Crash-sensing activation times or sensing criteria met Time from vehicle impact to deployment Diagnostic Trouble Codes present at the time of the event Ignition cycle count at event time Maximum Delta-V for near-deployment event Delta-V vs. time for frontal airbag deployment event Time from vehicle impact to time of maximum Delta-V State of driver’s seat belt switch Time between near-deploy and deploy event (if within 5 seconds) Passenger's airbag enabled or disabled state Engine speed (5 sec before impact) Vehicle speed (5 sec before impact) Brake status (5 sec before impact) Throttle position (5 sec before impact)
Limitations on Data’s Utility • Systems are designed to record information on frontal impact only • The calculation of the severity of the crash (the “delta v”is not exact and can be plus or minus 10% • In older vehicles, the seat belt data is recorded only for the driver
Ownership of the Data • GM takes the position that the data is the property of the owner of the vehicle. • What if the vehicle is leased? • Some automobile insurance policies contain provisions that may give the insurance company the right to retrieve “black box” data. • Do the police have the right to download the data?
Preserving the Data • Preserve an unbroken chain of custody! • Notify all investigators, insurance companies, counsel, tow truck operators, auto repair shop, etc. NOT to move or repair vehicle, or remove the EDR or to retrieve or attempt to retrieve any data from the EDR. • Get a TRO, if necessary.
The Law • Bachman v. General Motors Corporation, 2002 Ill. App. LEXIS 659 (Appellate Court of Illinois, Fourth District) July 29, 2002.
Conclusion • The EDR is not a replacement for the accident reconstructionist. • The EDR can be a source of additional data to confirm the conclusions of the accident reconstructionist. • The EDR may serve as an effective tool to impeach conclusions reached by accident reconstructionists who fail to consider the data generated by the EDR. • A lot of trial lawyers are going to be very busy litigating all of the issues the “black box” will generate during the coming years.