<BGSOUND SRC="laser.wav">

                             Crash Data Retrieval







Crash Data Retrieval Kit













Sensing Diagnosing Module's

Event Data Recorders

Diagnostic Link Connector



On-Board-Diagnostics (OBD) II



























Accident Analysis & Consulting, CDR Download Request Form

Sample CDR Report

California Vehicle Code Section 9951

Web Sites of Interest

Frequently Asked Questions


Accident Analysis & Consulting is certified by Vetronix Corporation/Bosch Group to operate Crash Data Retrieval Systems by General Motors (GM) and Ford.

Vetronix Crash Data Retrieval System
Downloads pre-crash and crash data from a vehicle's air bag module to a laptop computer. The Windows® based CDR software presents the data in easy-to-read graphs and tables.

Crash Data Retrieval System Overview

  • Downloads pre-crash and crash data from the vehicle's air bag module to a laptop computer.

  • The Windows® based crash data retrieval (CDR) software presents this data in easy-to-read graphs and tables.


What data can be downloaded from the vehicle's air bag module*

Recorded data depends on vehicle make, model and year. The following data is typical of what is found on a newer GM vehicle.
  • crash data retrieval system softwareVehicle speed (5 seconds before impact)
  • Engine speed (5 seconds before impact)
  • Brake status (5 seconds before impact)
  • Throttle position (5 seconds before impact)
  • State of driver's seat belt switch (On/Off)
  • Passenger's air bag enabled or disabled state (On/Off)
  • SIR Warning Lamp status (On/Off)
  • Time from vehicle impact to air bag deployment
  • Ignition cycle count at event time
  • Ignition cycle count at investigation
  • Maximum deltaV for non-deployment event
  • deltaV vs. time for frontal air bag deployment event
  • Time from vehicle impact to time of maximum deltaV
  • Time between non-deploy and deploy event (if within 5 seconds)

    *Depending on the particular vehicle, all or a subset of this data may be available.



Vetronix and General Motors
The relationship between General Motors (GM) and Vetronix began in 1984. GM selected Vetronix to develop the first event data retrieval unit in 1990 (GM use only). Afterwards, GM awarded Vetronix an exclusive contract to develop the crash data retrieval (CDR) system for GM and the aftermarket. The crash data retrieval (CDR) system became available to the public in March 2000.

Vetronix and Ford Motor Company
Ford contracted Vetronix to develop software that will interface with the Crash Data Retrieval System (CDR) and enable users to download crash data from select Ford Vehicles. The first Ford update (software and cable) was

Return to top

Frequently Asked Questions about the CDR system

Q: What is an air bag module?
A: The air bag module is the vehicle's “computer” that controls air bag deployment. Since 1990, recordable air bag modules have been installed in select GM vehicles. SDM, Sensing and Diagnostic Module, is the name given to air bag modules used in General Motors vehicles from 1994 to present.

Since 1998, recordable air bag modules have been installed in select Ford vehicles. RCM, Restraint Control Module, is the name given to air bag modules used in Ford vehicles from 1998 to present.

Q: Will data only be recorded if the air bags deploy?
A: No, data is recorded in both Deployment and Non-Deployment Events.

Q: What is a Non-Deployment Event?
A: There are two types of air bag module (SDM) recorded crash events. The first is the non-deployment event. A Non-Deployment event is an event severe enough to “wake up” the sensing algorithm but not severe enough to deploy the air bag(s). It contains Pre-Crash and Crash data. The SDM can store up to one Non-Deployment Event. This can be overwritten by an event that has a greater SDM recorded velocity change (Delta-V). This event will be cleared by the SDM after the ignition has been cycled 250 times (about 60 days of normal driving).

Q: What is a Deployment Event?
A: The second type of SDM recorded crash event is the Deployment Event. It also contains Pre-Crash and Crash data. The SDM can store up to two different Deployment Events, if they occur within five seconds of one another. The first deployment event will be stored in the deployment file (this would have been the event that deployed the air bag) and the second Deployment Event will be stored in the Near Deployment file. Deployment events can not be overwritten or cleared from the SDM. Once the SDM has deployed the air bag, the SDM must be replaced.

Q: Why are GM and Ford making this data available?
A: GM and Ford wish to collect air bag deployment and crash data in order to improve vehicle safety design. They also wish to support recommendations set forth by the NTSB and NHTSA.

Q: Do other vehicle manufacturers have recordable air bag modules, and if so, why aren't they releasing this data?
A: Yes, some other vehicle manufacturers have recordable air bag modules. The amount of information recorded and the Model Year that they began installing these recordable air bag modules differs for each manufacturer. The NTSB (National Transportation Safety Board) and the NHTSA (National Highway Traffic Safety Administration) have recommended that all vehicle manufacturers equip their vehicles with recorders capable of storing crash data.

Q: Has the CDR system been validated?
A: Yes, GM, Ford and Vetronix have worked together to ensure the accurate retrieval and presentation of the recorded data. In addition, independent validation tests have been performed by NHTSA, Michigan State Police, Ontario Provincial Police, and others.

Q: Are there validation studies and reports available?
A: Yes, several papers and studies have been published concerning CDR data validation. Please contact Vetronix for more information.

Q:What are the potential uses of the data?
A:EDRs can provide information about a crash that can't be obtained through more traditional investigation techniques. 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 design better airbag systems and vehicle structures.

EDR data may be useful in determining culpability. For example, EDR data from a car involved in an August 2002 crash in Florida showed the vehicle was traveling at 144 mph seconds before it struck another vehicle, killing two passengers. The EDR data was used to convict the driver of manslaughter.


Return to top