Bell the Hybrid - adding noise makers

[bwilson4web]

Hi,

This is a blood and broken bodies safety issue and needs to covered separately from range extender engines and EV vehicles. This may not be the best forum but it started from a thread here so ...

Originally Posted by Old Tele man

...does that mean EV's are like the prodigal kids, who should be "...seen, but not heard"?

It means noisy vehicles are already disproportionately causing pedestrian deaths and likely injuries. If we spend our time making the demonstrable safe vehicle as noisy as the deadly ones, we are not going to effectively reduce the pedestrian deaths and injuries. It is smacking the brother of the kid who pulled the stunt. But there is real science behind the flaws of vehicle noise as a pedestrian safety requirement.

There is a substantial range of audio levels from different vehicles, easily 30 dB. Because audio power levels vary by the inverse square law, a noisier vehicle further away will mask a quieter vehicle that is closer. That happened before the first hybrid and continues to this day. Ordinary gas vehicles are 'hiding in the noise.' More to the point, we just don't see credible data of a hybrid risk and there are more than enough Prius on the roads that any such risk should show up.

The first step is to look at the accident data and we find problems with drivers and pedestrians. My thinking is we need technical solutions such as the accident avoidance systems. These range from vehicle mounted cameras, both IR and video, and radar units. They can detect a pending collision and apply the brakes faster than the driver.

I also like the European model of having pedestrian safety ratings on vehicles. The combination of bumpers, hoods and quarter panels means:

• deaths -> injuries
• major injuries -> minor injuries
• minor injuries -> learning experience

If we could find any credible evidence of Prius risk to pedestrians, I could be persuaded. But instead we have a stinking, pile of pedestrian dead whose bloody fingers point at SUVs and pickups and all of the vehicles on our roads. Solve the problem, the one written in blood, first.

Bob Wilson

[Frank Lee]

Agreed.

Special interest groups/govt/nanny state wannabees have a hard time identifying and focussing on the REAL problems.

Sheesh, look at what's happening with alcohol/driving laws; it's INSANE.

[cfg83]

bwilson4web -

Yes, the context is a lot more complicated than "hybrids are quiet". But what studies are you citing? Does it take into account SUVs as a "percentage of the vehicle population"?

That said, I'm not into the radar stuff and I don't have confidence in auto-braking (yet). It seems like it would be cheaper and easier to have a speaker saying "I am a hybrid, I speak softly and carry a big battery", . Why not the engine noise of your favorite car? I could have a Cobra one day, chitty-chitty bang-bang another day.

CarloSW2

[RobertSmalls]

This topic has come up before on EM. My response: as a cyclist, I can tell you that efficient cars with good exhaust systems (so, most new compacts and green cars) can really sneak up on you. I maintain situational awareness using my ears, especially if I have to move in to traffic to make a left turn, or to avoid a hazard in my lane. A car with large, loud tires or a leaky exhaust can easily mask a Prius or a Civic, even once the loud car has passed and is pretty far away.

I don't think any legislation is needed, just extra caution on the part of all road users.

[NeilBlanchard]

Well said, Bob!

I'm remembering about a subtle change made to the Volt's hood: the seam was moved to the outside and down below the corner. The reason they did this is to reduce the stiffness of the hood in the likely area where a person' head would hit the car, if you were so unfortunate as to strike them while driving.

My point is, why does the Volt (and other cars, too -- I specifically have heard about Honda designing similarly) to protect pedestrians, when a truck or and SUV with it's "wall" of metal and knarly edges don't make any concessions -- in fact they are downright vicious in this regard.

[bwilson4web]

Hi,

I've reorganized the questions to make sure each is fairly addressed. I've been following the issue since the first legislation was introduced. Because I've been so close to the problem, I often state facts and data without a full bibliography and it is perfectly fair to ask for my sources. This note is just the original information request, quoted, and the source material pointers:

Originally Posted by cfg83

. . . But what studies are you citing?
Does it take into account SUVs as a "percentage of the vehicle population"?

"ANALYSIS OF BLIND PEDESTRIAN DEATHS AND INJURIES FROM MOTOR VEHICLE CRASHES, 2002-2006", Christopher Hogan, Ph.D, Direct Research, LLC, 226 Glen Ave., SW, Vienna, VA 22180, revised June 16, 2008.

To download a copy:
NHTSA-2008-0108-0007 at Regulations.gov

The types of vehicles causing pedestrian deaths broadly match the US distribution of vehicles (Table 3). Slightly more than half (45 percent out of 80 percent) of passenger vehicles involved in pedestrian fatalities were cars, slightly less than half were light trucks, SUVs, and minivans. A Prius was involved in 11 of the pedestrian deaths over this period, but none of the deaths of legally blind pedestrians.

Examination of the cars involved in blind pedestrian deaths over this period reveals no hybrids were involved in any blind pedestrian deaths (Table 4). As shown above, the most common class of vehicle involved in a blind pedestrian death was a pickup truck. (Note, however, that the differences between sighted and blind pedestrian deaths in Table 3 would not pass traditional tests of statistical significance.)

The second source comes from the NHTSA's own study, which I cited in my web page:

. . .
In Docket No. NHTSA-2009-0041, the NHTSA reported:

"While all passenger vehicle types (cars, sport utility vehicles, pickups, and vans) are involved in backover fatalities and injuries, the data indicate that backover fatality numbers show pickup trucks (72 of 288) and utility vehicles (68 of 228) to be overrepresented when compared to all non-backing traffic injury crashes and to their proportion to the passenger vehicle fleet." (pp. 6)

Again, you can use Regulations.gov or ask Google to get a copy. But pause a second and reread:

involved in backover fatalities and injuries

Where is the engine exhaust pipe located? It is in the rear ... the part that backed over and injured and killed the pedestrians.

Originally Posted by cfg83

. . . It seems like it would be cheaper and easier to have a speaker saying "I am a hybrid, I speak softly and carry a big battery", .
Why not the engine noise of your favorite car? I could have a Cobra one day, chitty-chitty bang-bang another day.
. . .

It depends upon how much one values an effective solution when human life and injuries are involved. In this case, we have records from the NHTSA hearing that address how effective noise is in traffic safety:

NHTSA-2008-0108-0018.1 Regulations.gov

Comments from Les Blomberg, Executive director of the Noise Pollution Clearinghouse:

. . .
Five general comments are described more fully below: 1) Noise Pollution is a serious environmental problem. 2) Hybrids are not silent vehicles. 3) Millions of vehicles, most of them not hybrids, are acoustically masked by environmental noise. 4) Amplifying masked sounds is not a solution for detection problems caused by masking in multi-dimensional situations (parking lots, streets, highways). 5) The solution to poor detection is to reduce masking noise, and hybrids are a part of the solution.
. . .

I came to the same conclusion when I realized that everyday, 24x7, we conduct "noise vehicle" experiments called 'traffic.' Since their invention, car engines have made a racket and promptly hit pedestrians. We're talking over a century of this experience. How long do we have to run the experiment?

In contrast, our species have applied our brains to car technology and:

• hydraulic brakes instead of mechanical - deaths went down
• safety glass - deaths and injuries went down
• seat belts and deaths and injuries went down
• collapsing steering gears and deaths went down
• air bags and deaths went down

I remember when accidents were always blamed on the "nut behind the wheel." In one respect, I agree ... let the car handle braking when the nut fails.

Originally Posted by cfg83

. . . .
That said, I'm not into the radar stuff and I don't have confidence in auto-braking (yet). . . .

At least a couple of times a week I walk into a building or mall where a radar operated door opens for me. When I walk my dog down the street, there are two houses with IR motion detectors that turn on their driveway lights. I have one on our car port for when I drive home after dark. I also have a key fob that will flash the light, honk the horn and lock and unlock my car from beyond stopping distance. I cite these commonly, available, remote sensing and activation systems because they are common, almost part of our everyday life. But there is one more.

In January 2009, I attended the Detroit Auto Show and saw the Denso display:







I watched in fascination as this system:

• identified and followed lanes
• identified pedestrians
• identified and read street signs

This is another system:


Asking for sources is always OK. This subject is peripheral to hybrid technology but falls in what I call "electro-political" when making the right engineering decision can be over-ridden by political issues having nothing to do with "doing the right thing."

Bob Wilson

[jamesqf]

Originally Posted by cfg83

Why not the engine noise of your favorite car?

Because my favorite (though I admit it's an imaginary ideal) car makes no noise at all?

Instead of forcing hybrids to make excessive noise, we ought to have stricter standards for effective mufflers on conventional cars.