[Quietcars] Washington Post article on silent cars

[Robert Wilson]

Hi,

We've been looking at Prius fatality rates and recently finished a study of the 2001-2007 fatal accidents. It is only fair to share our results in the same way that:

> But an as-yet-unreleased NHTSA study of accidents in 12 states 
> compares accident rates for some hybrid vehicles and their internal 
> combustion engine counterparts.
> 
> 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, said Ronald Medford, acting deputy administrator of 
> NHTSA. 'We certainly know that blind pedestrians rely heavily on the 
> sound of vehicles as a means of determining when it is safe to cross 
> the road,' Medford said. 'But all of us are susceptible.' The 
> potential problem arises at speeds less than 15 mph, when the 
> electric and hybrid vehicles are notably quiet, almost silent. At 
> higher speeds, the rush of air and the slap of tires makes the 
> electrics almost as noisy as their gasoline-powered counterparts.

* * * Summary * * *
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 just 12 states. Yet the fatality data for 50 USA states 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. 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 patterns.
* * * END SUMMARY * * *

Feel free to share this unpublished report summary.

Bob Wilson
 		 	   		  
_________________________________________________________________
Hotmail® has ever-growing storage! Don’t worry about storage limits.
http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutorial_Storage_062009