Applying Automotive EDR Data to Traffic Crash Reconstruction

EDR's are not new, but are becoming more prevalent in part due to a new federal regulation. 49 CFR, Part 563, which affects vehicles produced after September 30, 2012, will result in a standardized and publicly available EDR in 90% of new vehicles. Accident Reconstructionists frequently have trouble reconciling EDR data with other data sources, and improvements in ABS technology result in fewer tire marks visible at the scene of crashes to allow calculation of pre-crash speeds without an EDR.

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 any current and future EDR data set without regard to manufacturer. The class presents the generic analysis step by step, then groups EDR"s 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
    • Case Study - vision of success
    • Overview - EDR data availability by manufacturer by model and model year
    • 49 CFR Part 563 EDR regulation timing and contents
  • 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
      • 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
    • Speed at impact drills
    • Accelerator pedal release and brake application
    • Using Delta V to obtain closing speed and impact speed
    • Delta V data accuracy
    • GM EDR families - data availability and limitations, and case studies
      • Using Longitudinal Delta V to get speed at impact in angular collisions
      • Using speed data in critical speed yaw single vehicle crashes; transforming speed vs time into speed vs. distance to impact
      • Reconciling EDR data to scene evidence and evaluating uncertainty in inline collisions
      • Multiple events - which event is my recording from?
    • Ford EDR families - data availability and limitations, and case studies
      • Ford PCM - evaluating when criminal or negligent behavior occurs, transforming speed vs time data to speed vs distance and overlaying on map to evaluate sight lines
      • Ford ACM - using Delta V in inline collisions and stability control system longitudinal acceleration data to determine real time drag factor
    • Chrysler EDR families - data availability and limitations, and case studies
      • Using acceleration data to calculate Delta V
      • Using yaw angle data to sub-topic
    • Toyota EDR families - data availability and limitations, and case studies
      • Using RPM and Delta V to determine speed when actual speed is above data limitation
      • Data latency
    • Honda, Mazda, and other manufacturer EDR families (to the extent they are known at the time of the class)
    • EDR data admissibility technical foundation