Googling on ("event data recorders" automobiles) will give a lot
of hits.
For example:
http://wpoplin.com/EventDataRecordersAutomotiveBlackBoxes.pdf
These devices are a byproduct of the introduction of
airbags - the airbag processor stores the data which led it to
deploy the bag.
This can include
delta v
vehicle speed
engine speed
brake use
throttle position
driver seatbelt use
The cited report claims they only store the most recent 5 seconds
of data, snapshotted at 1 second intervals. It notes that the data
can thus be confusing - for example, if a wheel leaves the ground
the speed reported can be way off, and if the driver pumps the
brakes, the 'brake use' data is ambiguous. It's not clear whether they
store data continuously, or just when the airbag deploys.
OTOH, I seem to remember reports of drivers of high-end cars (Audis?
BMWs?) getting their warranties invalidated because the main car
computer noted that they had exceeded certain speeds during the
break-in period.
Its not just the airbag computer that can narc you out....
Peter
