[SystemSafety] NHTSA claim concerning safety correlation of Tesla SW

Peter Bishop pgb at adelard.com
Fri Mar 1 18:50:33 CET 2019


It all boils down to how NHTSA have handled

- Mileage before Autosteer

- Mileage after Autosteer

For some vehicles Mileage Before is unknown and this was assumed to be
all "mileage after"
- even though there were quite a lot of airbag deployments in the Before
category

However, there is a subset where the "mileage before" and "mileage
after" data appears to be complete,

For this subset, the airbag rates/million miles were:

Before: 0.76 +- 0.13

After:  1.21 +- 0.15

If we take the best case "after" scenario for the full data set we get
the result in the NHTSA report

After:  0.81 +- 0.08

To be more realistic, we can adjust the "after" mileage by estimating
the missing "before mileage" and subtracting it from the "after mileage".

The missing "before mileage" can be estimated using

"Before airbag deployments"/Before airbag rate (OK subset)

The top end estimate for this rate is

Airbag_before rate: 0.76 +0.13 ~ 0.90

This removes the least possible After mileage

Using this adjustment on the full After mileage data set we get:

After(adjusted): 0.93 +- 0.07

If this analysis is correct, adding AutoSteer makes little or no
difference to the airbag deployment rate

Peter Bishop

Adelard

On 27/02/2019 08:30, Peter Bernard Ladkin wrote:
> I think this is important. It comes directly from the researchers.
>
> https://catless.ncl.ac.uk/Risks/31/8#subj3
>
> PBL
>
> Prof. Peter Bernard Ladkin, Bielefeld, Germany
> MoreInCommon
> Je suis Charlie
> Tel+msg +49 (0)521 880 7319  www.rvs-bi.de
>
>
>
>
>
>
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-- 
Peter Bishop
Chief Scientist
Adelard LLP
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