Remember 'Unintended Acceleration'

Well it has come to the Tesla community. So I shared this:
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Thank you for "Dr. Ronald A. Belt’s Sudden Acceleration Papers".

I have an intermittent message on my Model 3 about 'Unable to shift because accelerator is pressed.' A couple of quick flaps clears the condition and I can then shift and drive off. I typically see this about once per week and figured eventually to swap out the accelerator to clear the problem.

I was driving a first generation Prius when the 'sudden unplanned accelerator' brew ha ha erupted. The first Prius version used a dual potentiometer sensor that could easily wear to a point car would go into 'safe home' mode. The next generation used dual Hall effect sensors that were not subject to this wear problem. But limping home in 'safe hold' was only dangerous from other traffic.

Once people learned the brake controller recorded the last "n" seconds, the reports of unintended acceleration rapidly disappeared. Accident investigators have access to these readers.

There was a latent defect traced to unsecured floor carpets and mats from the death of the Saylor family in a Lexus. My second Prius was delivered without floor clips to hold the driver side, floor mat down which I corrected by driving back to the dealer two days after taking delivery. I got the clips and properly installed them!

There was a 'tricky' way using a decade resistance box to show a potential problem to non-technical reporters. This identified a problem of dual sensors using both ascending or descending voltages from the dual sensors could command acceleration. A better approach in German cars was one sensor ascending and the other descending.

Uncommanded acceleration can occur:

• 99.98% - stomping on the accelerator instead of the adjacent brake pedal
• 0.01% - unsecured floor mats or loose objects (aka. shoes) in the driver footwell
• 0.005% - fraud trying to blame the car for the driver's screw up
• 0.004% - previously undiagnosed, latent defects, usually takes more than one OR cosmic ray
• 0.001% - act of God or otherwise unreproducible and undiagnosed problem(s)

WHAT TO DO IF IT HAPPENS TO YOU

Shift to "N" by raising the shifter lever for a couple of seconds.

Regardless of what the car is doing, you can always shift into "N" and the car will no longer accelerate. To be safe, you MUST practice this at least once! It also works if you have a driver problem who needs a 'time out.'​

The criticism of the Belt paper sound reasonable to me. Especially about the "100 amp" overload of the 12 V lead-acid battery.

Perhaps an end-of-life lead acid battery or the newer LiON battery might lead to the reported voltage sag. I haven't read the paper and other than going to the parking lot and rapidly swinging the steering wheel while monitoring the 12 V battery buss, I'm not willing to make a call. My 12 V battery was replaced less than a year ago so it is still fresh.

In my work and home history, I have seen multiple cases where marginal power supplies have made digital electronics behave badly. Whether the "Belt" hypothesis can be replicated determines my course of action.

Bob Wilson