Some guy on the evening news claimed it was the vehicle's "black box recorder"
Some of the airbag controllers I have seen are quite simple and independent.
They would not be logging data.
I would think the ECU is more likely to do this. I believe they store
maxima for the last engine start: things like speed, RPM, temperature.
The ones in the stretched Ford in this accident have accelerometers in
them that store the impact Gs, as well as brake on/off, throttle
position and impact angle (in this case that isn't needed as the thing
hit hard enough that the engine was inside the cabin after impact.
They are pulling all stored data they can as everyone involved died.
So far the limo company itself seems to be very shady and the various
"limos" they have have failed many inspections and still are on the
road. The driver wasn't licensed with a passenger endorsement.
The road where it happened is also a bad stretch, all downhill to a T
with only a stop sign and one stop ahead warning prior to the sign.
The vehicle not only was speeding it dropped into a deep ditch area and
STOPPED! No energy dissipation at all.