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Hybrid cars are good for the environment. But scientists say that they might be bad for pedestrians. Because hybrids are so quiet, it can be hard for walkers to hear them until it’s too late. Listen to this. [quiet car sound]
That’s a Toyota Prius moving at five miles an hour. If you didn’t hear anything, well, that’s what worries scientists at the University of California, Riverside. They recorded the sounds made by an approaching hybrid vehicle and by a car with a standard, internal combustion engine. They then asked listeners wearing headphones to determine whether the car was coming from the left or the right.
Turns out people could hear the standard vehicle from about 36 feet away. But the hybrid was able to sneak up to just 11 feet away before listeners knew where it was coming from. And when the scientists added some background noise, people couldn’t pinpoint the direction of the Prius until it had already passed them by, results they’ll be presenting at the May meeting of the Acoustical Society of America in Portland, Oregon. The solution, they say, is to require a “minimum sound” for all late model cars. No annoying beeps or alarms. Just something to supply that new-car sound.
—Karen Hopkin
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22 Comments
Add CommentWe do not need more noise. My Prius is quiet because of its construction. It is NOT dangerous to pedestrian because I'm paying attention when I'm driving. A noisy vehicle driven by an inattentive driver is still more dangerous. Adding noise to a quiet vehicle will not make it safer, only more noisy. It's time we realize that the driver is responsible for following the laws of the road and for watching for those around him/her. It's also the responsibility for the pedestrians to watch out for vehicles when crossing roads. If a pedestrian steps into traffic without looking and there is a car too close to respond, there will be a problem ... regardless of how much noise the car makes. So, let's address the real problem, not come up with stupid ideas like making more noise.
Reply | Report Abuse | Link to thisWhat I would like on my Prius is a little sweet-sounding bell, like a bicycle bell. Then I could warn that jogger I am creeping up on.
Reply | Report Abuse | Link to thisSeriously rmludwig? Why yes I agree that people should just be more attentive, it is unreal to believe that we should just stop there. The fact of the matter is, a noisier car from the outside WOULD help, period. Also, how about the blind? This would greatly help them for the inattentive drivers.
Reply | Report Abuse | Link to thisYES, drivers should be attentive. YES, pedestrians should be attentive too. But it's good to know that if you are walking on the side of the road and you can hear that car coming up behind you.
Perhaps pedestrians should use their eyes and be cautious instead of just expect that since they have the right of way, no one will ever accidentally hit and kill them.
Reply | Report Abuse | Link to thisIf you are stepping into an area where any traffic is, LOOK BOTH WAYS and be careful. If you are incapable of using your senses, perhaps you shouldn't be steeping into an area where you could be killed. Just a thought... sheesh.
Realizing that the driver is responsible for following the laws of the road does not guarantee that all drivers will follow the laws of the road. It will be small comfort to the family of a dead pedestrian, especially a child pedestrian, to know that the driver was responsible for following the laws of the road. Even among those who are not negligent, drunk, or using their cell phones, human perception and attention are limited and pushed to their limits when performing the task of driving. Accidents happen. Glossing over this issue under the rubric of individual responsibility is just irresponsible.
Reply | Report Abuse | Link to thisThis issue and its premises are pure nonsense! The article itself borders on the manufactured, ethical, neo-journalistic style of our day. The fact of the matter is that there is no issue here. Are we really hurting for valid news? Aren't there enough headlines? Osama Bin-Laden needs a haircut! Babies are born toxic and genetically deformed! Oprah bough a new nail clipper! Report on that! Give us, your arbitrary, voluntary readers, something of substance!
Reply | Report Abuse | Link to thisNow, getting back to the core of the matter, there is, in fact, a very, very, very, very simple solution. Have the car manufacturers work with their engineers to incorporate into the design a "people warning horn" akin to the already existing "deer warning horns." With the right amount of ingenuity, the sound can actually be made to please the human ear without setting every dog in the neighborhood into a howling frenzy. A simple whistle with an airy, fluttery sound would even suffice. It may be enough to simply mold the chassis in a way that the air passing over it produces sound. Check with the aero-engineers who are constantly struggling to eliminate sound in the airplane designs. If any one on this earth knows about vehicular sound and acoustics, it woud be this crowd. Finally, whatever sound is required, it should not be any louder that the sounds currently produced by traffic. The last thing we want is to read more creative articles about a new phenomenon you will surely spin as the "human hypno-whistle effect." You will even resort to the quaint acronym HuHy-WE and make it sound whistly! Your buzz words, not mine.
There's no need to scrap an entire techonology, for lack of noise. Besides, cars will still contain horns. Right? Simply because a vehicle produces less noise, the fact shouldn't preclude the prerequisite for an attentive driver. Now I'm wondering... Should bicycles make more noise? There are actually higher incidences of pedestrian-bicycle collisions in NYC than there are motor vehicle accidents. If all else fails, the manufacturers can include factory installed,, and consumer uninstallable, tin cans to the rear bumper. They could even include a warning label: "Removal of this mechanism is punishable by law and subject global reversion back to pre-hybrid models!" Hmmm... Honk if you agree!
We have owned our Prius for 5 years, and I have been aware that pedestrians can't hear the Prius when it's backing up after the first week of ownership (especially in parking lots). The quietness of the hybrid did take some getting used to at first. I would notice pedestrians walking in front of the car unexpectedly more often than my former car. After I realized this, I adjusted my driving and always assume pedestrians don't see or hear me.
Reply | Report Abuse | Link to thisI am a very careful driver (still, no one is perfect), but that doesn't mean all Prius drivers will be extra careful. Drivers and pedestrians can be distracted and not pay attention to others around them.
I agree that unnecessary excess noise is annoying, but we are talking about a small warning signal, not a loud unmuffled engine. If it saves one person's life, the small annoyance of a bit of extra noise would be worth it.
As long as were on the subject, why are motorcycles allowed to be so excessively loud? I know some claim it makes them more safe so the big bad cars and trucks to blindly run into them, but as they come boom boom booming through my neighborhood at night, they rattle my windows and I'm left wondering if we aren't being excessive there....
Reply | Report Abuse | Link to thisThanks parkfive. I know when I'm walking through the parking lot I pay attention to engine idle sounds to determine if someone is about to back up. When approaching from the side its just about impossible to see the reverse lights on a vehicle. Obviously thats all a pedestrian can do. The rest is up to the driver to check mirrors and still back out of the spot at an appropriate speed. I always back up six inches pause then continue backing slowly.
Reply | Report Abuse | Link to thisOh! And to all the stupid car manufacturers out there...those white lights on the back of a vehicle....those are called reverse lights. Not the I'm an idiot and it helps me find my vehicle so I'm going to turn them on whenever someone unlocks the door lights.
I read an article about this last year
Reply | Report Abuse | Link to thishttp://www.nano-shells.com/silent-cars.html
It's certainly a valid point. People assume they can hear cars; so having silent cars would be very dangerous.
You're all missing the point. Does it really take scientists (Acoustical Society of America) to figure out a simple fact that they may pose a threat by being too quiet? Frickin ridiculous! Oh BTW all you Prius drivers who think you're privledged or special because you paid too much money for your little status symbol can kiss my behind. You should take a look at the enviromental nightmare that those batteries have become & how much more enviromental waste & Co2 emissions go into manufacturing one than a standard small car.
Reply | Report Abuse | Link to thisWhat's easier to execute? Adding some kind of sound to the cars or making sure every single driver is paying attention at the wheel AND making it so that pedestrians themselves aren't sometimes retarded? Sometimes it's not the fault of the driver. And even when it is, any bystanders should have a way of knowing what's coming. Until we figure out some other ways to be on our toes, this low-tech method seems likely to help.
Reply | Report Abuse | Link to thisPedestrian Killed by Golf Cart ; Customers Found Yelling in Noisy Restaurant ; University Teaches Critical Thinking and Problem Solving . These are headlines that you've not seen for obvious reasons. (Someone please tell me that this study was published on The Onion.com and not SA). Please write to your congressional representative and tell them to enact legislation that by 2020 no vehicle manufactured or offered for sale in the USA shall emit any sound at any time louder than 60 dBm excluding a horn used for emergency warnings. The technology exists today to enable this. Many of you have sound reducing headphones, a similar technology could be used to reduce vehicular noise. But hey, why stop with vehicles? AC or neighbor pool pump keeping you from opening your windows at night? The list is quite long. If this is defined as a technological problem, it requires a technological solution. Perhaps it is a behavioral problem and requires behavioral changes. Have you seen the signs on the payment in Britain Look Right ?
Reply | Report Abuse | Link to thisWhere is the study that says any deer was saved by those devices? None exists. The problem too much noise, not too little.
Reply | Report Abuse | Link to thisSeriously? I love the fact that my Prius is so quiet. Yes while I do agree that the blind community does have to deal with the danger of quieter cars, if pedistrians are wearing a headset and walking or running it is the job of the pedestrian to be watching for cars not listening. This is just ridiculous, and if we're going to put noise makers on Priuses we need to put them on bicycles too.
Reply | Report Abuse | Link to thisWow! If I have to add noise to my Prius, I'm going to put a loud speaker on it and play a recorded rev like a Harley continuously whenever my speed drops below 5 mph. If a Harley gets to make obnoxious noise, so will I! VRRROOOOMMMM, VROOOOMMM, VROOOOMMMM!!! CAN YOU HEAR ME NOW???
Reply | Report Abuse | Link to thisBefore Hybrid/electric car came out to the market, I already notice that some car high end petrol are just start getting too quiet for the road.
Reply | Report Abuse | Link to thisSound is very important for people on the road for people to aware a car is somewhere near them which is out of there sight.
Just one of my own example. Once I nearly got driven over by a drunk motorcyclist on a country road, luckily I can hear that his motorcyclist is driving straight to my back and I can react in time and get out of his drive path.
This sounds like "problem" manufactured by someone who does not make electric or hybrid vehicles. Probably in response to that advertisement bragging about how quiet a hybrid car was. I notice the article does not mention who funded this study. Want to bet it was someone like Chrysler? Personally, I have much more problems with people in big vehicles expecting everyone to get out of their way than Prius owners not being careful enough.
Reply | Report Abuse | Link to thisI do not have a hybrid, but my car is pretty quiet, so I am always on the lookout for oblivious pedestrians in parking lots and crosswalks. No big deal. It's called defensive driving, what we are all supposed to be doing anyhow.
If there is any "problem" here, it is that there are not enough quiet cars around, so people do not expect them. As they continue to get more popular, I expect people will not be as surprised any more.
We need statistics to back up the argument before looking for unnecessary solutions.
Reply | Report Abuse | Link to thisSmall low level sounds when in built up ares and reversing for awareness can be generated artificially if necessary . but the sound of conventional cars on freeways are the height of human social destruction.
Reply | Report Abuse | Link to thisSo many people live in noisy environments and it is not so much the sound but the frequency volume and how long it is sustained.
It is also depends on the state mind and mental awareness of the recipient of the sound ,that is all important.
So i think the reduction of sound not just of the engine but of all parts of the car that affect noise should be looked into.
Noise is the result of Wasted Energy, so from a climate standpoint lower noise levels means lower energy usage?
Noises can be made to be emitted from cars in only one direction; for example a sound could be directed forwards only so there would be little noise over spill to annoy other persons within the near area.
Reply | Report Abuse | Link to thisI agree with the noise problem, and I would like to add a further observed difficulty. The regenerative braking system on the hybrid vehicles make the car slow faster than expected. While following a Prius on the city street at 35mph at approximately 4 car lengths, the Prius driver and I noted the light ahead had turned red and we (probably) took our feet off the accelerator at the same time to coast to the intersection (about 12 car lengths ahead). I found myself have to (unexpectedly) brake to avoid rear-ending the Prius.
Reply | Report Abuse | Link to thisI think we may need the brake lights to activate on hybrids whenever they are decelerating as well.