My earlier post regarding the Saylor family Toyota crash may have
sounded to some as if I was suspicious of a conspiracy or suicide as the
root cause. Also, in light of recent news, a little clarification may
help.

The "suspicious" part of this accident is how the expert driver managed
to make the absolute worst choice in exiting the freeway at that point
with an uncontrolled vehicle. That ramp sloped downward, to a busy "T"
intersection, with very bad terrain just beyond the intersection.
Indeed, the Saylor vehicle hit another vehicle in the intersection, then
went airborne due to encountering the terrain, and finally was engulfed
in fire once it stopped.

It may have simply been a very bad choice to exit the freeway at that
point and time, but we must concede that the driver was probably pretty
busy and distracted at the moment. Also, this location is one of the
rare instances where a freeway terminates with the straight-ahead lanes;
to continue on the freeway here, you need to be in the two right
(logically the exit) lanes. (The straight-ahead lanes are intended to
continue the freeway North, at some undetermined future date.)

Recent news is that a professor at Southern Illinois University has
demonstrated uncontrolled acceleration by a single fault "short"
condition of the redundant throttle position sensors. (Better details
were not reported.) Toyota is backtracking from their initial
pronouncement that the throttle system cannot have any electronic
problems.

My view at the present is that the possibility of a software problem is
probably much higher than an electrical or electro-mechanical problem.
We will have to wait for more facts, but the facts so far seem to be
pushing Toyota's confidence back one step at a time.


Ed Price
ed.pr...@cubic.com     WB6WSN
NARTE Certified EMC Engineer
Electromagnetic Compatibility Lab
Cubic Defense Applications
San Diego, CA  USA
858-505-2780
Military & Avionics EMC Is Our Specialty

> -----Original Message-----
> From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of
Richard
> Nute
> Sent: Wednesday, February 24, 2010 12:29 PM
> To: John Woodgate
> Cc: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: Toyota
> 
> Hi John:
> 
> 
>  > There do seem to be some very odd features about this incident. Why
>  > wasn't the CHP officer making the 911 call, instead of the
> hysterical
>  > person who did?
> 
> The CHP off-duty officer was driving with his family
> in the auto-dealer courtesy car.
> 
> I guess he was pretty busy trying to control the car
> (at 160 km/h), so his wife made the call.  (I think
> there's a web site where you can listen to the call.)
> 
>  > However, that is beside the point. Now that the focus has turned to
> EMI
>  > being involved, and the practical impossibility of testing for all
>  > conceivable EMI threats, I think we are looking towards a
> *mechanical*
>  > emergency throttle closer and/or fuel cut-off.
> 
> 
> Have you ever had a computer lock up?  Was it due to
> EMI?  Re-cycle power and everything runs normal.  And
> no trace to the cause of the lock-up.
> 
> We owned a 2005 Toyota Avalon.  We believe it incurred
> an uncommanded acceleration which ended when we rear-ended
> the car in front.  This was moderate acceleration for a
> long up-hill on-ramp to a freeway.  Not fast, but it took
> 2 feet on the brake and it slowed but not stopped until it
> hit the car in front (which was stopped).  At the time, we
> blamed the brakes, but in light of the recent info, we now
> believe it was an incident of uncommanded acceleration.
> After front-end repair (including re-cycling the power),
> the car worked normally for as long as we owned it.
> 
> 
> Best regards,
> Rich

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