A UC professor just did a study on hybrid's being dangerous for the blind.

Here's video of the news report.

http://www.instantriverside.com/rive...nd/2008/04/17/

When I followed the link, all I got was the text without video. I don't know if the video had additional details, but the text makes it clear that they didn't find hybrids were dangerous, just that they had the potential based on the fact that they couldn't be heard as well when traveling at speeds under 20mph.

So to review, you can't hear hybrids coming as easily when they're going under 20mph. That's it. Nothing else has been demonstrated.

Whenever I run into a blind person with my HCH2, it seldom results in a fatality since I drive so slowly....

Spartybrutus;

I didn't see that one coming...

LOL

All I found was a text article that claimed they had to be "40% closer" to be of equal volume. This sounds as if the original source is 100 feet away, the Prius would need to be 40 feet closer or 60 feet away. So this let's us calculate the relative amount of noise:

V1*(d*d) = V2*(.6d*.6d)
V1*(d*d) = V2*(.36*d*d)
V1*(d*d) = V2*.36*(d*d)
V1 = V2*.36

According to this 'professor', the Prius volume is 36% of the volume of the unknown reference vehicle. So all Rosenblum and the blind are demanding is for every Prius owner to triple their volume compared to some unknown vehicle.

What is fair is to demand the blind increase their audio acuity by 3 times, 4.8 dB, or the amount easily handled by a hearing aid. BTW, if the professor meant ".4," the 0.16 power factor is still less than 10 dB, ~7.96 easily handled by low cost hearing aids.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

bwilson4web — I compute a power ratio of 0.36 to be -4.4 dB, and one of 0.16 to be -8.0 dB. Don't forget the factor of '10' in order to get decibels from bels:

# decibels = 10*log[10](power ratio)

Stan

You are absolutely right!

Calculating dB is trivial once you figure it out. I failed to include the factor of 10 multiplier.

Thanks,
Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

http://www.latimes.com/classified/au...,5690461.story

[Jana] Littrell, who is blind, was walking through a bank parking lot in the East Bay town of Albany a year ago when her foot was run over by a Toyota Prius backing out of a parking space. She wasn't injured and the driver apologized effusively, she recalled.

Might be the first known incident of a hybrid "collision" with a blind person. Of course, I do have to wonder how many people are injured or killed each year by drivers of non-hybrid vehicles backing up.

Here are just a few such stories recently in the news I found on Google News.
http://www.news4jax.com/news/15724902/detail.html
http://www.wsoctv.com/news/15817051/detail.html
http://www.tcpalm.com/news/2008/mar/...-face-charges/

Did she hear the backup beep?

I think the blind advocates realize the traffic data does not support their point of view. One of the standard features in the Prius #6 package is a backup camera. Today I was riding with the driver and I recommended she 'back-in' to her parking place for fuel efficiency reasons. However, with a backup camera, it is also a safety feature since forward visibility when first driving off is much better going forward. Some people call this 'fancy parking' but it has been part of the Prius FAQ from the earliest versions.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.