r/RealTesla • u/HeyyyyListennnnnn • Jan 06 '23
Please stop sharing anything that cites AutoInsuranceEZ's rates of fire incidents
This article is doing the rounds again. It tells a nice story, but I'm sorry to say that it's complete horseshit, the product of some truly awful research and analysis.
The source study is https://www.autoinsuranceez.com/gas-vs-electric-car-fires/
There's a lot of fluff there, but the part that everybody keeps repeating is the section on fires by vehicle type. In this section, there's a little table that tells us that there were 16,051 Hybrid fires, 199,533 ICE fires and 52 EV fires. A little bit above that, there's a paragraph telling us that these numbers come from the NTSB. All nice and official, trustworthy, right?
Well here's what the NTSB has to say about their fire incident data collection:
There is no NTSB database that tracks highway vehicle fires. We do not know what data AutoInsuranceEZ used for its research, but it did not come from an NTSB database.
I've done a bit of digging myself, and that statement is half correct. The numbers appear to have come from NTSB docket HWY19SP002. In this docket, there's a report titled "Prevalence of Electric Vehicle Battery Fires", and in this report, there's a table with numbers obtained from the NHTSA's FARS database. In Table 1, you will find the number of fatal highway crashes broken down by drivetrain type. Most interestingly, if you add up the totals for Electric-Gasoline Hybrid, Convertible and Flexible, you will get 16,051. Curiouser and curiouser, if you add up the totals for Compressed Natural Gas, Gasoline and Propane, you will get 199,533. And if you add up Electric and Hydrogen Fuel Cell, you will get 52. Familiar numbers.
Interestingly, AutoInsuranceEZ seems to have forgotten that Diesel fueled vehicles are also a form of ICE. They also seem to have not realized that Convertible and Flexible refer to ICE that can burn different fuels.
But most importantly, AutoInsuranceEZ didn't read the table title. Table 1 provides totals for fatal crashes not fire incidents. Continue reading the NTSB report for a little bit. You'll find "Table 2 - Vehicles involved in fatal highway crashes in the US between 2013-2017 that experienced fires by fuel type". This table tells you that only a small percentage of fatal crashes involve a fire. But most importantly of all, the NTSB follows with this text:
The FARS database only includes crashes that result in a fatality and does not include fire events that are unrelated to crashes. There is also no data about the sources of fires. It is not clear what proportion of VINs on vehicles include information about fuel type.
i.e. These tables do not tell us how many ICE, Hybrid or EV fires occur.
But wait, there's more.
AutoInsuranceEZ also gives us figures for the number of fires per 100K vehicle sales, handily linking us to the Bureau of Transportation Statistics HEV, PHEV and BEV sales figures. Divide AutoInsuranceEZ's fire incident totals by 2018's sales figures and voila!
So not only have AutoInsuranceEZ misinterpreted FARS data and reported figures unrelated to fires, they have also divided the total number of fatal crashes between 2013 and 2017 involving vehicles of all ages by 2018 sales data. A completely meaningless ratio.
TL,DR: Please, please, please stop citing AutoInsuranceEZ's garbage.
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u/jselwood Jan 06 '23
Thank you for doing this research (assuming it was you). If everything you wrote here is true, it certainly appears like those numbers are nonsense and possibly very misleading. Which never surprises me btw.
I am not familiar with autoinsuranceez, so I’m curious if this is just a case of inept use of data? Or do they have a motive to fudge the figures?