<div class="section abstract"><div class="htmlview paragraph">The objective of this study was to quantify the field performance of passenger
vehicle event data recorders (EDRs) in recording data into non-volatile memory
at the 8 km/h delta-v (Δ<i>v</i>) trigger threshold specified by Title
49, Part 563 of the Code of Federal Regulations (Part 563). Part 563 applies to
passenger vehicles manufactured on or after September 1, 2012. The trigger
threshold is distinct from the threshold required to deploy an airbag. Events
meeting the trigger threshold will cause data to be preserved on the EDR even if
airbags are not deployed. This is the first study to quantify EDR trigger
threshold performance. This data is valuable in the evaluation of sub-airbag
deployment crashes. The study was accomplished via analysis of EDR and
reconstructed Δ<i>v</i> data from 3,960 cases in the Crash
Investigation Sampling System (CISS) database maintained by the National Highway
Traffic Safety Administration (NHTSA). The binary presence or non-presence of an
event on the EDRs of vehicles exposed to a collision was compared to the CISS
reconstructed Δ<i>v</i> for each vehicle. Logistic regression models
were developed to predict the probability of an event present on the EDR at the
trigger threshold. We found that vehicles manufactured by Toyota had lower
Δ<i>v</i> thresholds compared to other manufacturers. For Toyota
manufactured vehicles, the probability of an EDR event at 8 km/h ranged from 87%
to 99%. EDR event probabilities for non-Toyota vehicles in vehicle-to-vehicle
collisions ranged from 58% to 93% for Part 563 compliant vehicles and 33% to 83%
for pre-Part 563 vehicles. The persistence of EDR events in memory was analyzed
using the number of ignition cycles present between events and imaging of the
EDR, finding average duration of 3,595 ignition cycles for pre-existing EDR
events unrelated to the CISS case.</div></div>
