a traffic crash reconstructionist wanted to know the speed of a car in the
seconds before it crashed into the side of a school bus, he found that
information, and more, in the car's Event Data Recorder (EDR),
a feature quickly becoming standard on all cars. The recorder, a four-inch
square metal box, is currently installed in most recent GM, Ford, Chrysler and
Some commercial truck engines also have electronic control modules that will
hold vehicle data that can be recovered following a crash.
some ways similar to data recorders used on airplanes and trains, the car's
recorder springs into action as part of the air bag system.
designed to improve air bag performance based on the severity of the
collision, the event data recorder can tell traffic accident investigators
about the car's speed, engine RPMs, how far the accelerator pedal was pressed,
if the brakes were applied, whether the driverís seatbelt was buckled and
what warning lights were on.
an an air bag deployment collision accident occurs, the data is recorded onto
a computer chip. The data can be retrieved and is presented in a
data download from the EDR will usually contain 6 to 8 pages of information. A
second impact can be recorded in the secondary, or non-deployment, file
depending upon the circumstances of the collisions and the time interval
air bag deployment is not required for information to be recorded. There are
circumstances where an air bag deployment command would be issued but the
algorithm used to order the deployment determines a deployment is not
warranted, such as a driver out of position before deployment is ordered. This is
a "deployment level" event. Data may be recorded for
"non-deployment" events. This can include rollover, sideswipe and
side impact accidents.
It is also possible no data can be recovered from a
data recorder. One situation where this might occur would be a catastrophic
loss of electrical power during the collision. In this situation, the entire
power reserve in the air bag control module capacitor is used to deploy the
air bags; there is none left for the recorder and no data is stored even
though the air bags deployed.
Due to the variety of circumstances in any accident and variations in the type
and amount of data any device is capable of recording, there are no guarantees
of what data may be recorded, or may be recoverable, in any specific case.
Data Recorder downloads are completed by factory trained technicians at Harris
Technical Services. The technician is also a fully qualified traffic accident
reconstructionist. It is important the downloaded information and the physical
evidence be considered as a whole and the data between the recorder and the
physical evidence be compared before coming to any conclusions.
you would like more information, or need to arrange the recovery of data from
an event data recorder, please contact
us. The initial file review and consultation is free
and without obligation on any traffic accident case.
Links to additional information:
Vehicles with an EDR on
Supported vehicles include Acura, BMW, Buick, Cadillac,
Chevrolet, Chrysler, Dodge, Fiat, Ford, Geo, GMC, Holden, Honda, Hummer,
Infiniti, Isuzu, Jeep, Lancia, Lexus, Lincoln, Mercury, Mitsubishi, Nissan,
Oldsmobile, Pontiac, Rolls Royce Saturn, Scion, Sterling, Suzuk, Toyota and
Please call us at 772-336-2279 for information on what data
is recorded in specific vehicles.
Examples of EDR Files
These are example files of the recovered data. Not all
vehicles will report the same amount or type of information. Please call us at 772-336-2279 for information on what data
is recorded in a specific vehicle.
(Airbag Control Module)
(Powertrain Control Module)
Electronic Control Module Field Guide (Trucks)
This guide identifies Caterpillar, Cummins, Detroit, Mack and Mercedes
truck engines with recoverable data. This document was prepared by the
Wisconsin State Patrol Technical Reconstruction Unit. This information is
current as of March, 2010.
EDR Case Law
United States and Canadian trials where evidence from a Motor Vehicle Event
Data Recorder was introduced.
Statutes on Motor Vehicle Event Data Recorders.
Full text of all state EDR statutes. The
information is current as of February 03, 2013.
Federal Regulation (49CFR563) on Motor
Vehicle Event Data Recorders
This is the August 2006 federal regulation on EDRs.
of Event Data Recorder Data for Vehicle Safety Improvement
U.S. Dept. of Transportation, National Highway Traffic Safety
Administration, DOT Report 810935, April 2008.
Outside the Black Box: How creative thinking turned an electronic safety tool
into a criminal informant.
article is by Mary W. Craig, Associate Professor of Law at Faulkner Universityís Jones School of Law in Montgomery, Alabama.
Dept. of Transportation, National Highway Traffic Safety Administration, Final
Rule, 49 CFR Part 563, Event Data Recorders, Aug. 21, 2006.
Final ruling by NHTSA on 49CFR563.
Federal Regulation (49CFR563), NHTSA,
Final Rule; Response to Petitions for Reconsideration
This document responds to several petitions for
reconsideration of the August 2006 rule.
Event Data Recorders - State Statutes and Legal Considerations
This article, by Jim Harris, Harris Technical Services,
appeared in the Accident Reconstruction Journal, Vol. 18, No. 1, Jan/Feb 2008.
The Double Edged Sword that is
the Event Data Recorder
A 2006 paper by
Andrew (Sandy) Askland, College of Law,
Arizona State University, on EDRs and privacy.
for the Recovery, Maintenance and Presentation of Motor
Vehicle Event Data Recorder Evidence (12/05).
Evaluation of Event Data
Recorders in Full System Crash Tests, National Highway Traffic Safety Administration, Paper
Searching and Seizing Computers and Obtaining Electronic Evidence in Criminal Investigations, Computer Crime and
Intellectual Property Section, U.S. Dept. of Justice, July
Use of Event Data Recorder (EDR) Technology
for Highway Crash Data Analysis, National Cooperative Highway
Research Program, Transportation Research Board of the National Academies,
Project 17-24, December 2004.
A Review of Jurisprudence
Regarding Event Data Recorders:
Implications for the Access and Use of Data for
Transport Canada Collision Investigation, Reconstruction,
Road Safety Research and Regulation.