Vehicle Fires

In 2022 (the most recent year of data for the NFIRS) there were a reported 108,533 passenger vehicle fires. Yes, that’s a lot – about 8.6% of all fires in the nation. First, let’s see which states have the most car fires, as a percentage of all reported fires

Hawaii and the deep South lead the way, so maybe it’s heat and humidity causing engine fires? Drivers cranking their A/C to the breaking point? Maybe, but then next on the list are Alaska, North Dakota, and Michigan. They don’t fit that pattern. If it’s weather related, then you would expect to see more car fires in the heat of summer. You do, but not much, and only by the amount of extra driving that happens in summer. The following chart shows this:

Car fires go up in summer, but only because people drive more. So why are there differences from state to state? Maybe certain makes and models of cars are popular in some states, and those cars have more fires? We don’t have state-level data on vehicle makes (manufacturer), so that question will remain unanswered for now. But let’s take a look at the data we do have. The NFIRS data includes the vehicle make in each report. The top 20 most common makes:

Make	Number of vehicle fires (2022)
Chevrolet	14,217
Ford	14,203
Dodge	7923
Toyota	6215
Nissan	5103
Honda	4573
General Motors	3346
Hyundai	3134
Jeep	3059
Kia	2918
BMW	2219
Chrysler	2196
Buick	2057
Mercedes Benz	1416
Volkswagen	1409
Subaru	1354
Pontiac	1289
Cadillac	1113
Mazda	1059
Acura	1013

Of course, this doesn’t tell you much; there are more Chevys and Fords out there than any other make, so it’s not surprising that more of them are on fire. What we really need to do is adjust this based on the number of cars on the road for each make. The data is available for late 2021, which is a close enough match for this analysis of 2022 fire data¹https://numberthoughts.ebydurbin.net/data/Total-vehicles-in-operation-by-manufacturer-in-US-through-Q3-2021.pdf. The following table lists the same top twenty manufacturers, from most fires to least, per 10,000 vehicles in operation:

Make	Fires per 10,000 vehicles on the road
Pontiac	6.5
Dodge	6.4
Buick	4.9
Chrysler	4.9
BMW	4.4
Kia	4.1
Chevrolet	3.6
Cadillac	3.6
Hyundai	3.5
Acura	3.4
Ford	3.3
General Motors	3.2
Nissan	3.0
Mercedes Benz	2.9
Volkswagen	2.8
Jeep	2.6
Mazda	2.2
Honda	1.9
Subaru	1.9
Toyota	1.8

But that’s still not quite right. The age of vehicles in operation varies widely from make to make (the last Pontiac, for example, rolled off the assembly line in 2010; on the other hand there are many more new Teslas than old ones). And older cars are more likely to have fires than newer ones, for two reasons. One, over the years cars are built with higher safety standards. Two (more importantly), older cars are more ‘worn out’, and thus more likely to fail in some serious or catastrophic way. How do we know this is the case for car fires? The NFIRS reports include the year of manufacture of the car. And the “cars on the road” data breaks down vehicles into two groups: those 0-5 years old, and 6 or more years old. Combining these two produces the following table:

	Vehicle age, 0-5 years old	Vehicle age, 6 or more years old
Number of Vehicles	94,420,536	189,373,832
Number of car fires2Vehicle age is not always provided, so these numbers are extrapolated	9077	99456
Car fires per 10,000 vehicles	0.96	5.25

That’s right, older cars have five times as many car fires as newer ones. So maybe we shouldn’t be too hard on Pontiac. In fact, we can create an “adjusted car fire rate” by taking into account how many old cars are in the fleet of each make. Pontiacs are 100% old, so their rate will be adjusted the most. On the other end of the spectrum, Subarus are the ‘youngest’ set of cars on the road (of the twenty listed above), and so will be adjusted the least.

So, here’s the top twenty once again, taking into account the age of the cars on the road. The highest risk of fire (Dodge) is set to 1.0; all other numbers are relative to this.

Make	Relative Fire Risk
Dodge	1.00
Kia	0.93
Pontiac	0.87
Buick	0.85
BMW	0.84
Chrysler	0.78
Hyundai	0.74
Cadillac	0.62
Chevrolet	0.61
Acura	0.60
General Motors	0.57
Nissan	0.57
Ford	0.57
Mercedes Benz	0.56
Volkswagen	0.54
Jeep	0.52
Subaru	0.44
Mazda	0.43
Honda	0.35
Toyota	0.32

What’s the lessen to be learned? If you really want to avoid car fires, go for a late-model Toyota or Honda.

Back to individual states – why do some have an excess of car fires? I think the reasons vary from state to state. Hawaii tops the list, despite the fact that most of their car fires happen with relatively safe manufacturers like Toyota, Honda, and Mazda (they actually lead the US in car fires in each of those models). My guess is that it’s a combination of hot weather and tourists pushing rental cars to their limits (on an average day, about 17% of the people in Hawaii are tourists). Maybe the locals also drive their cars too hard, but it’s fun to blame the tourists.

Florida is next. Again, a warm state with lots of tourists. Sure, let’s keep blaming the tourists. Georgia’s next – probably can’t blame the tourists here, so maybe just hot/muggy weather? Although, if that’s the case, why are there more car fires in Georgia in December than any other month? Sigh. After that, it’s Alaska. How does that state fit in? It is a state of extremes (very cold winters, long distances), so cars probably get pushed harder and wear out faster.

Earlier I asked if perhaps certain states had a high rate of car fires because of the popularity of high-fire-risk vehicles. This appears to be the case with Michigan. The top four fire-prone makes are Pontiac, Dodge, Buick, and Chrysler. Car fires involving these manufacturers are much more common in Michigan, so we can infer that these makes are popular in the state (not surprisingly, since it is the historical center of US automobile manufacturing). I won’t swear to it, but seems like a reasonable explanation.