Black Box, Sensors, & Air Bags
THE BLACK BOX EXISTS: Most people don't know that their car
may have a little black box that records critical data called the Event Data
Recorder (EDR) from accidents & near accidents (much like the data recorder
in airplanes only much simpler & smaller). Data like speed at impact, G
force of impact, duration of impact & intensity over time of impact, whether
the driver was wearing the seat belt & did it work, how long the brakes
were applied for before impact, did the wheels lock up, etc. Car manufacturers
often don't want you to know about this little black box, possibly because it
reveals data that can reflect poorly on the performance of passive restrain
systems (airbags) & this could cause potential law suites, or force manufacturers
to make their air bag sensors better (extra cost means less profit).
THE GM DEALER: I actually learned about the existence
of a black box (it's under the drivers seat) in my wife's 1998 Safari
minivan (corporate twin to the Astro minivan) from the local General
Motors dealer when we had our car repaired after a low speed crash
on December 26/2002. The GM dealer told me that the local university
has a accident reconstruction department & had the equipment
to read the data in this black box. This black box isn't reusable
after an accident & the air bags have deployed, so I asked the
dealer to hold onto the black box so the university could examine
it's data. My concern was that my wife was considerably bruised
from the drivers air bag in an extremely low speed crash that should
never have set off the air bag & I wanted to see that it didn't
happen again to her, me or others. I was told that the air bag was
not supposed to go off in a frontal accident unless the speed was
in excess of 15 kilometers per hours (about 10 miles per hour),
but in this case it did (clearly a malfunction or lack of accurateness
in the single stage sensor). The GM dealer admitted that based on
the lack of any significant damage to the minivan other than a slight
ding on the front bumper, the air bag should not have gone off.
Unfortunately the GM dealer didn't honor my request to keep the
black box sensor (it got thrown out by the repair shop). I think
he wished that he had never told me about it's existence.
IT SHOULDN'T HAVE HAPPEN: Fortunately I took detailed pictures
of the accident scene which the university accident reconstruction department
was able to use along with examining the bumper & weight of the other vehicle
to determine for sure that my wife's Safari minivan was traveling under 7 kph
& in fact was almost stopped at the time of impact, so the air bags should
never have gone off. Transport Canada confirmed the findings of the university
& registered the incident as yet another GM vehicle with poor quality sensors
which allowed both frontal air bags to go off when they shouldn't. Besides seriously
bruising my wife's hands & arms, the insurance bill to replace the air bags,
sensor & bumper was almost $5000. CDN. (for a vehicle that had a wholesale
value of about $10,000 at the time). This was paid for by the insurance company
& our insurance rates did not go up from this accident because my wife was
not at fault, but ultimately we all pay higher insurance premiums because of
faulty air bag sensors (if you're in Ontario, you've probably noticed your car
insurance premium has gone up by 30 - 50% in the last 2 years).
MORE DISCOVERIES: I discovered that on newer GM Safari &
Astro minivans from 2001 on, GM equipment them with a more accurate 2 stage
sensor that was much less likely to deploy the air bag when it shouldn't in
a low speed crash, but GM wasn't able or willing to put this new sensor in our
1998 Safari minivan to prevent the same thing from happening again. I also discovered
that many European car manufacturers had put the much better 2 stage sensor
types in their vehicles some 10 years before GM got around to doing it. The
whole experience clearly said to me that GM cares far less about the safety
of it's customers, than it does about the profit margin it would lose if it
had to pay for a slightly more expensive sensor & didn't have all these
needless air bag replacements to prop up the income of it's dealers.
BIG BROTHER :-) We also have a 2000 Astro minivan which is
virtually identical to the Safari minivan, so I asked the university accident
reconstruction department to plug the black box of the Astro into their equipment.
It actually revealed an incident a month or so earlier when I was traveling
a bit too fast making a left turn during a snow storm (black ice) & the
front tire bounced off the curb, enough to throw my steering wheel out of alignment,
but not enough to deploy the air bags. I had recalled jamming on my brakes in
plenty of time & pumping the brakes (even though I didn't need to because
I have an anti lock braking system) & the little black box reveal exactly
what I had remembered happening, how long I had applied the brakes for, the
G forces of the bump off the curb & even the fact that I was wearing my
seat belt. It even accurately recorded the speed I was going before applying
the brakes, but wasn't able to record the speed properly after applying the
brakes because I was skidding on black ice & it revealed that the anti-lock
brakes were working properly. So be careful, because there's this tattle tale
black box in your car, big brother is watching you :-) There have been incidents
where drivers were convicted based on the information in the Event Data Recorder
box.
CBC MARKETPLACE: On January 13/2004 CBC aired
a half hour documentary on it's Marketplace
show.
By Doug Hembruff.
December 2, 2003
|