Applying Automotive EDR Data to Traffic Crash Reconstruction

EDR's were first installed in 1994 and are now installed in 99% of new light vehicles sold in the US. In the US EDR’s are not required, but vehicles with EDR’s made after 9/1/2012 must meet minimum standardized content requirements of 49 CFR, Part 563 including speed, throttle, brake on/off and Delta V.  Data must be retrievable with a publicly available tool.  Only a few manufacturers install EDR’s worldwide currently, but the EU and China are adopting regulations to require them in the next few years.  Some manufacturers provide stability control system data far beyond the US regulation that aid in understanding vehicle movement in the 5 seconds prior to the crash. 

This course will provide the participant with the skills necessary to analyze EDR data that has already been imaged, apply it to crash reconstruction, and reconcile it with calculations using other data sources. The course will enable the participant to analyze current and potential future EDR data set without regard to manufacturer. The class presents the generic analysis step by step, then groups EDRs into manufacturer-specific families and their data limitations, and works case studies that highlight targeted key learning objectives. The student will also learn key points to satisfy court Frye and Daubert requirements for EDR data to be admissible, and suggest methods to present EDR data that will communicate the data understandably to attorneys and lay juries. 

This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 20 Continuing Education Units (CEUs). Upon completion of this seminar, accredited reconstructionists should mail a copy of their course certificate and the $5 student CEU fee to ACTAR, PO Box 1493, North Platte, NE 69103.

What Will You Learn

By attending this seminar, you will be able to:
  • Describe EDR sensor operation, recording interval and duration, resolution, accuracy, and time latency and articulate the limitations of applying the data to crash analysis
  • Calculate min and max speeds prior to loss of control or braking, and at impact based on the last accurate EDR pre-crash speed data point
  • Evaluate EDR vs. actual ground speed for specific vehicle operational conditions and vehicle equipment modifications
  • Calculate speed at impact and closing speeds by combining EDR Delta V data with normally collected scene and vehicle data such as post crash travel distance, departure angle, drag factor, and vehicle weights
  • Apply data to inline rear end, head on, and angular collisions
  • Reconcile EDR data with other physical evidence and combine to narrow speed ranges
  • Use time-distance and overlay EDR data on scene maps/diagrams to show where critical driving inputs were made vs. inputs required to avoid collisions

Is This Course For You

This course is a must for anyone involved in the investigation and analysis of passenger car and light truck crashes who needs to understand the types of event data that are available, the limitations of that data, and how to apply it to a collision reconstruction and reconcile it with data from other sources. In addition, this course can be valuable to insurance adjusters and claims managers, and attorneys handling automotive collisions. Engineers designing EDR's to meet part 563 regulations may also benefit from understanding how the data they store will be used. New analysts requiring training, as well as experienced analysts who require information on changing technology and federal regulations will find this course relevant and timely.   

Materials Provided

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Course Requirements

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  • Overview
    • Overview – current status of EDR’s in the US and worldwide
    • EDR data availability by manufacturer by model and model year
    • US 49 CFR Part 563 EDR regulation
  • EDR Data Analysis
    • Rules of recording and data limitations - Is this recording from my crash, and which of my multiple events is this recording(s) from?
    • Speed data accuracy during operation before a crash
      • Six vehicle operational conditions where EDR speed is not ground speed, including wheel slip during heavy braking
      • Three vehicle equipment modifications that make speed data inaccurate
      • Data latency and other data limitations like resolution, truncation or rounding to the resolution, exceeding maximum values, and default values
      • Data accuracy test data/literature review
    • Calculating Speed at impact from the last EDR recorded speed
    • Accelerator pedal release and brake application
    • Using steering, yaw rate, and lateral stability control acceleration data when available
    • Using distance to impact vs time to impact – overlay data on google earth photos
  • Source of Delta V information
  • Calculate Delta V of 2nd vehicle, inversely proportional to weight of 1st
  • Using Delta V with post crash travel to obtain impact speed
  • Combining two Delta V’s to get closing speed – with adjustments for restitution and offset
  • Delta V data accuracy
  • Reconciling EDR Speed Data, Speed from RPM, Speed from Delta V and post crash travel, Speed from closing speed from Delta V, and traditional sources like momentum
Day Three
  • GM EDR families - data availability and limitations
    • Dividing GM EDR’s into 5 different major groups (2021 Corvette #6?)
    • Characteristics of each major group
    • 2010+ Group “3.5” records in order events qualify not the order they start
    • 2013+ Group “4” part 563 intent
    • 2021 Corvette?
  • Ford EDR families - data availability and limitations, and case studies
    • Early Ford ACM – limited value
    • Ford PCM 2003-2011- putting data into proper time order
    • Ford 2009+ with stability control system data
      • Speed at impact from last stable speed and SC longitudinal accel
      • Calculating Cumulative Heading change in turns
      • Using heading change in emergency avoidance to estimate approach angle change and sideways movement
      • Using SC lateral accel to determine approach angle change and sideways movement
      • Anomalies in 2009-10 RC6, 2012-15 AB10
  • Chrysler EDR families - data availability and limitations, and case studies
    • Using acceleration data to calculate Delta V in 2006-2009’s
    • Using yaw rate (same as in Ford 2009+)
  • Toyota EDR families - data availability and limitations, and case studies
    • Dividing Toyota into families, characteristics of each family
    • Record rear impacts from first models
    • Upper speed is limited on Gen 1 & 2, Using RPM and Delta V to determine speed when actual speed is above data limitation
    • Toyota differences from other manufacturers: lateral data from side algorithm wake up, not frontal algorithm wake up, for different time intervals and durations
    • Data latency in Gen 1 & 2 Toyotas
    • Toyota Vehicle Control History and Crash Avoidance data
  • Honda – records speed displayed on speedometer (delayed from true speed)
  • Nissan – has EDR in some 2006-2012 you can get them to read for you
  • Mazda, Volvo, BMW, Mercedes, VW and Subaru CDR-supported data  
  • Kia/Hyundai – data in 2010-2012 models not officially supported, Jag/Land Rover, Saab, some Mitsubishi – all not supported by Bosch CDR system but with EDR data
  • Discussion of Advanced Driver Assistance Systems (ADAS) and the information some may record
  • EDR data admissibility technical foundation