Prius fatal accident rate is 50% lower

bwilson4web · Sep 28, 2009

I've been working on Prius accident data inspired by Christopher Hogan's pioneering work. Recently, the NHTSA leaked a preview of their 12 state study so it is time to publish these results:

The Prius fatality rate of 0.64 per 100 million miles is less than half of the NHTSA 1.37-1.51 fatalities per 100 million miles for the years 2001-2007. This is based upon the annual Prius sales from 2000-2007 minus an overly high estimate of 3% Prius lost per year; an annual usage of 15,000 miles per Prius per year; and 75 prorated deaths of the 124 fatalities from 111 fatal accidents including Prius and non-Prius vehicles.

The Prius went on sale in the USA in 2000 and by 2007, 515,944 had been sold. However, some of these vehicles were lost by accidents, theft, and other disasters. Using the Automotive Salvage Association numbers for all salvage and the Department of Justice numbers for vehicle theft, we came up with an overly high estimate of 3% Prius loss per year. We used 15,000 miles per year, the same number the EPA uses for annual mileage, to calculate the Prius miles per year, 2001-2007, and came up with 11.8 billion miles.

Using the National Highway Traffic Safety Administration (NHTSA) Fatality Accident Reporting System (FARS), we found 111 accident records that included a Prius with a total of 124 fatalities. However, the Prius was less than 60% of the vehicles involved in these accidents giving a pro-rated, Prius fatality count of 75 deaths 2001-2007. Divide these 75 deaths by the 11.8 billion miles and scale it to deaths per 100 million miles and the number is 0.64 per 100 million miles for 2001-2007. During this same interval, the NHTSA reported 1.51 to 1.37 fatalities per 100 million miles, more than twice the fatality rate of the Prius. There have been 11 Prius-only, pedestrian fatalities in this same period. This gives a Prius-only pedestrian fatality rate of .093 pedestrian fatalities per 100 million miles.

Recently, the NHTSA leaked that a hybrid is 50% more likely to be involved in a pedestrian accident from a study of fatal and non-fatal accidents in 12 states. Yet the fatality data for all of the USA shows the Prius to be 50% less deadly. This makes sense when we realize that Prius are likely to be found in urban areas driven by owners whose driving pattern involves more miles than the average driver.

"Quality Planning" reported in July that hybrid drivers average 25% more "non-commuting miles" than ordinary drivers or roughly an extra 2,000 miles per year. People who have to drive further distances are going to be attracted to fuel efficient hybrids so this makes sense. Quality Planning went on to report a 63% higher rate of traffic citations, a number close to the 50% higher pedestrian accident risk from the NHTSA. Again, this reflects driving in a denser, urban area with more miles than an average driver. Yet in spite of these additional risk factors, the Prius remains less deadly by half than ordinary vehicles.

Congress is considering legislation that mandates higher noise levels on hybrid electric cars to make them as noisy as ordinary cars. But given the higher traffic citation rate reported by "Quality Planning," making more noise won't change driving habits that lead to more citations.
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It is risky to criticize an unpublished study based upon a news report that leaked some summary data. The NHTSA, twelve state study needs to be studied in depth before failing away at it. Regardless, we have enough fatality data to publish how deadly the Prius is relative to the NHTSA reported fatality rate. The leaked "50% more likely pedestrian accident rate" stands in stark contrast to the fatality rate. However, the higher citation report, "63%," seems to be in the same general area.

I've drafted my first web page but haven't put it online, yet. I have to add all of my footnotes and references. But this posting pretty well describes the methodology and results. It is my "leak" of another report on Prius fatal accident rates.

Bob Wilson

a64pilot · Sep 28, 2009

I have been hoping for lower than average accident rates / fatalities etc., because I'm hoping for lower insurance rates.
Gotta be a little careful with crash test ratings etc., because they don't tell the whole story. Back in 93 when I bought a Camaro to take to Germany and run the Autobahn, it tested really well in the crash tests. I believe it was the "safest" American made car of it's class. In 94 when the accident statistics came out, you were more likely to be killed in a Camaro than any other car of it's class. So, it's the reason people that bought a particular car, drive that car, also has an effect on the accident statistics.
If there is a big advertising campaign on how safe a car is, it has a tendency to attract people that are safe drivers and are looking for a safe car and the accident rates reflect this.
If on the other hand, the advertising campaign is on how fast and sporty a car is, the tendency is to attract people that may drive fast and sporty and have may higher accident rates doing so.
I hope that most of us Prius drivers are over there in the right lane seeking higher mileage and driving safe.

steve44 · Sep 28, 2009

BWILSON, is there a link you can share that compares (or simply allows you to select) other cars' fatality records? I'd greatly appreciate it.

bwilson4web · Sep 28, 2009

steve44 said: ↑

BWILSON, is there a link you can share that compares (or simply allows you to select) other cars' fatality records? I'd greatly appreciate it.
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I'm using the NHTSA summary at:
http://www-nrd.nhtsa.dot.gov/Pubs/811124.PDF

You can find similar reports for each year.

I had considered trying to get something online but I would need an accurate count of the number of vehicles and their annual miles ... the fleet data. Unfortunately general sources of vehicle fleet data tend to be proprietary.

The FARS data, the actual fatality record, is publicly available but the fleet data needed for the vehicle miles is the problem.

LATE NOTE: 2008 FARS data is available. I'll be busy updating the spreadsheet shortly.

Bob Wilson

donee · Sep 28, 2009

OK,

So what this says, is that because a Prius is likely to be driven in areas where Pedestrians are common - urban areas - then they need to make noise. But its the very noise in these areas that make these any vehicle a hazard to pedestrians in such areas. Because such noise covers up approaching vehicles. Indeed, every time I have nearly been hit by a vehicle as a pedestrian, this has been the case. So, more noise is just going to make things more dangerous to pedestrians in my opinion.

Sounds like they lost the statistics battle, so now they are out to make up a an artifice to push this through. Outrageous!

bwilson4web · Sep 29, 2009

donee said: ↑

. . .
So what this says, is that because a Prius is likely to be driven in areas where Pedestrians are common - urban areas - then they need to make noise. But its the very noise in these areas that make these any vehicle a hazard to pedestrians in such areas. Because such noise covers up approaching vehicles. Indeed, every time I have nearly been hit by a vehicle as a pedestrian, this has been the case. So, more noise is just going to make things more dangerous to pedestrians in my opinion.
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That was part of what came out in the June 23, 2008 hearing. Gas-only cars today are 'hiding in the noise' and that already frustrates blind pedestrians.

donee said: ↑

. . . Sounds like they lost the statistics battle, so now they are out to make up a an artifice to push this through. Outrageous!
Click to expand...

We don't have a copy of the NHTSA 12 state study so we don't know the details of their methodology. We only have this conclusion:

Medford said:

Covering more than 8,000 hybrid electric vehicles and nearly 600,000 gasoline-fueled cars, the analysis suggests that during certain low-speed maneuvers such as turning and backing up, hybrid vehicles are 50 percent more likely to be involved in an accident with a pedestrian, . . .
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I remain intrigued by how "turning" and "backing up" were quantified versus other vehicle operations like "driving forward."

Bob Wilson

bwilson4web · Sep 30, 2009

steve44 said: ↑

BWILSON, is there a link you can share that compares (or simply allows you to select) other cars' fatality records? I'd greatly appreciate it.
Click to expand...

Ok, this is still a 'work in progress' and subject to change. Heck, I don't even have a change log, yet, and the HTML is primitive. Regardless, this is my 2001-2007 Prius fatality report:

Prius Fatalities 2001-2007

I take all comments and criticisms in the spirit they are given and I am not the least bit offended if you help identify a problem early.

Thanks,
Bob Wilson

cossie1600 · Sep 30, 2009

its never the drivers fault!

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