Accuracy of EDR 5 second Pre-Impact Speed calculations
Posted: Mon Oct 10, 2022 1:42 pm
A recent post on another forum included question on EDR reporting data:
The pre-impact speed is generally determined by taking an average of the wheel rotation for the drive wheels (front wheels, rear wheels, or ALL wheels).
Things that can affect the recording of wheel speed and calculation of vehicle speed are
We found a sample Chrysler report (vehicle 1) which demonstrates wheel rotation differences, etc
Here is the crash diagram
Here is the last second of Vehicle speed and wheel speeds:
Here is the overall event:
Here is the data from the report pages 17-20
- For the 5 second pre-impact reporting for speed etc how much scatter is there when a vehicle is yawing and/or skidding pre-impact?
Does the EDR under or over report?
The pre-impact speed is generally determined by taking an average of the wheel rotation for the drive wheels (front wheels, rear wheels, or ALL wheels).
Things that can affect the recording of wheel speed and calculation of vehicle speed are
- wheel slip,
- wheel braking,
- wheel loss of contact with ground
- any bumps cause any tire to loose contact with roadway?
- tire inflation
- different wheel radius
We found a sample Chrysler report (vehicle 1) which demonstrates wheel rotation differences, etc
Here is the crash diagram
- CISS sample.png (82.82 KiB) Viewed 4967 times
- EDR ore impact Speed Closeup -1 to 0.png (58.68 KiB) Viewed 5020 times
- EDR Pre impact speed -5 to 0.png (52.71 KiB) Viewed 5020 times
- See the full 20181011056_V1_ACM.PDF Report)
- EDR report p 17-20.png (784.53 KiB) Viewed 5020 times