Are Cars Too Sound-Proofed for Drivers to Hear Emergency Vehicles?

In summary, the favorite radio station thread reminded me of an experience while renting an SUV. I got an SUV as a rental vehicle last year for a visit to my sister (it came in handy for hauling around relatives and getting stuff to a park for my nephew's birthday). At one point, I had the radio on softly (my mom hates the car radio on and she was a passenger - that was somewhat fun to finally turn the tables on her, "I'm the driver and if I say the radio stays on, it stays on.") It was summer, the windows were up and the A/C
  • #1
Moonbear
Staff Emeritus
Science Advisor
Gold Member
11,923
54
The favorite radio station thread reminded me of an experience while renting an SUV.

I got an SUV as a rental vehicle last year for a visit to my sister (it came in handy for hauling around relatives and getting stuff to a park for my nephew's birthday). At one point, I had the radio on softly (my mom hates the car radio on and she was a passenger - that was somewhat fun to finally turn the tables on her, "I'm the driver and if I say the radio stays on, it stays on.") It was summer, the windows were up and the A/C on (I prefer windows down, but again, mom's a pain in the butt, and it was easier to turn on A/C than listen to her groaning about being too hot). Traffic was all stopped for a red light, and I watched an ambulance fly past with lights flashing...and I didn't hear a sound! There's no way they went through an intersection without a siren, but I swear, I didn't hear a thing. I had to crack the window to double check that they indeed had a siren on. I was shocked! Those things are so well sound-proofed, that you cannot hear a siren if you have the radio on and windows closed (I don't think the blower contributed much to noise, unlike in my little, non-luxury car where I have to keep the fan low to hear the radio over the blower). I didn't even have the radio playing loudly at all, unlike many others on the road who probably have far more noise inside their vehicles, like louder music, children squabbling, or whatever.

I also recently watched a very near collision between a fire truck and an SUV. The fire truck was coming to the intersection, sirens and lights blazing, blowing their horn as they approached the intersection, and an SUV just kept driving right through the light. Other cars sitting at the intersection tried beeping their horns at the SUV as it showed no sign of braking. I was on the sidewalk and stood back from the corner fully expecting a collision. It was really a narrow miss. After my experience driving an SUV, I really had to wonder if that driver could even hear the sirens. Because of the buildings around the intersection, I know it's hard to see anything coming down the road, so you would have to have reason to stop before the intersection to see anything coming before entering, and the SUV had the green light, so no reason to slow down if they didn't hear the sirens.

Anyway, this left me wondering if in an attempt to appease consumer demands for luxury cars that block out the road noise, have the cars become so well sound-proofed that they are unsafe? You need to be able to hear a siren, or a horn beeping, or that loud motorcycle in your blind spot (especially in a vehicle such as an SUV where there are large blind spots). People playing loud music also contribute to this problem in a less sound-proofed car. There are also deaf drivers. In all of these situations, even if you are an attentive driver, once one sense is cut out from detection of your surroundings, this seems to pose a real saftey risk.

So, part 1 of this question: do you think this is a real problem? Have any of you experienced the same thing, either with the radio too loud or in a well-soundproofed vehicle that an emergency vehicle whizzed past with lights flashing and you never heard the siren?

For part 2 of the question, what is the best way to resolve the problem? We can ask auto manufacturers to no make their cars quite so well sound-proofed, but I can't see them agreeing when there is consumer demand for it, nor does that help in the case of loud radios and deaf drivers. One thought I had, with no idea if such a thing is possible to design and install in a car, is some sort of external detector on a vehicle that would pick up on certain sound frequencies. Most car horns are tuned to the pitch of 'A,' right? Or is that myth? And emergency vehicle sirens seem to have a pretty well-defined pitch range as well that is not too common in the environment (or they could even be equipped with a transmitter at a specific frequency that would operate at an optimum range for drivers to respond to them and that this receiver in the cars would be able to detect - so that you're not picking up on the police car 4 blocks over, just the one approaching your intersection or coming up from behind you).

Now, what would this receiver do when it detected sirens from an approaching emergency vehicle? Perhaps something like either turning off the radio, or cutting the volume down to the lowest setting so you can get an auditory cue, whether it's the radio going quiet, or finally being able to hear the siren over it. In addition, perhaps a flashing dashboard light, something to provide a visual cue to those who cannot hear the siren, either because of an overly sound-proofed vehicle, or deafness.

Do deaf drivers have any sort of similar equipment already available to provide them with a visual cue of approaching emergency vehicles? At night, the flashing lights on emergency vehicles are easy to notice, but in bright daylight, they just aren't as noticeable, and if the vehicle is approaching from an intersecting street, they may be out of view until too late.

Even if it isn't possible to replace the ability to detect all sounds, and it certainly won't replace the need to pay attention to your surroudnings, at least in the situation where there's an emergency vehicle approaching an intersection, it seems something is needed. Of course, unless it is required as an aftermarket installation, which may be impossible depending on what else is included in the same circuit as the radio, this could only be gradually implemented through installation on new vehicles, so is not going to be a quick or immediate solution to anything.

Oh, and yes, I'm aware that there are some traffic lights equipped with devices that emergency vehicles can use to change the lights to stop traffic, but given that emergency vehicles sometimes need to make a wide turn, and into the opposing lane to get around stopped vehicles, it may be more useful to have something that alerts the driver that the don't just need to stop for a red light, but really should be getting over to the right and out of the way.

In summary, here are the three main questions I've asked: Is this a problem that needs resolving? Is my idea of a receiver that provides an auditory and visual alert to a driver a viable solution to the problem? Is there a better or more easily implemented solution to the problem?
 
Physics news on Phys.org
  • #2
You could have the ambulances carry radio transmitting equipment so if you have the radio on that's a plus, not a minus.
 
  • #3
I think, also that the fan may have had more to do with it than you think. I have an air filter that is absolutely worthless except that it produces white noise. When it's too loud outside I just turn it on and suddenly everything's blocked out.
 
  • #4
BicycleTree said:
I think, also that the fan may have had more to do with it than you think. I have an air filter that is absolutely worthless except that it produces white noise. When it's too loud outside I just turn it on and suddenly everything's blocked out.

In my own car, the fan is pretty loud, so no doubt it contributes in some (many? most?) cars. In that monstrosity I was renting, it was surprisingly quiet, but either way, having the A/C or heat on with windows closed is a pretty common thing, whether the problem was solely the sound-proofing or a combination of sound-proofing and fan noise.
 
  • #5
BicycleTree said:
You could have the ambulances carry radio transmitting equipment so if you have the radio on that's a plus, not a minus.

Wouldn't you need to be tuned to a specific frequency for that to help? Or do you mean as a supplement/modification to my separate receiver idea, to transmit a radio message through that instead of just quieting the radio? I was thinking the easiest thing would be a switch in the circuit leading to the radio to cut power to it (perhaps with a reset button so you can return to your music once alerted), or if it can be incorporated directly into the radio design, it could control volume, or do as you suggest, automatically tune to a frequency to provide an audio message.

Maybe just a flashing signal on the dashboard is enough. Would there be a huge uproar and resistance to purchasing something if it could turn off your radio on you? Could tech saavy hooligans use it to transmit their own nonsense to your car radio? There's already some problems with the receivers on traffic lights due to people figuring out the frequency and misusing it to give themselves green lights and causing accidents by rapidly switching lights.
 
  • #6
Cars should not be soundproof and car radios should be limited to a low volume. You're driving a car for god sake not sitting in the lounge chair in your living room. You could kill someone.

While we're at blocking out all outside noise and putting in surround sound stereos in our cars, why don't we get rid of those pesky windows? All that visual stimulation detracts me. :grumpy:

I just want to get into my car, turn it on, put it in gear, lean back and close my eyes while listening to my favorite tunes and cruising down the highway.
 
Last edited:
  • #7
Moonbear said:
Wouldn't you need to be tuned to a specific frequency for that to help? Or do you mean as a supplement/modification to my separate receiver idea, to transmit a radio message through that instead of just quieting the radio? I was thinking the easiest thing would be a switch in the circuit leading to the radio to cut power to it (perhaps with a reset button so you can return to your music once alerted), or if it can be incorporated directly into the radio design, it could control volume, or do as you suggest, automatically tune to a frequency to provide an audio message.

Maybe just a flashing signal on the dashboard is enough. Would there be a huge uproar and resistance to purchasing something if it could turn off your radio on you? Could tech saavy hooligans use it to transmit their own nonsense to your car radio? There's already some problems with the receivers on traffic lights due to people figuring out the frequency and misusing it to give themselves green lights and causing accidents by rapidly switching lights.
No, I mean transmitting the siren across all radio frequencies. So the siren comes over your radio.

Any modification to the car is probably going to meet with resistance. It's the ambulances' problem and car companies aren't going to cooperate without a lot of incentive. Much better to put stuff on the ambulance than on the car.

Another solution is just to make the siren louder, or to allow it to focus sound onto specific non-responsive cars (as I understand it this can be done).

On a bicycle you can hear everything much better than in a car. That's the best solution from the consumer end. Plus, bicycles don't block the road.
 
  • #8
Evo said:
I just want to get into my car, turn it on, put it in gear, lean back and close my eyes while listening to my favorite tunes and cruising down the highway.

:rofl: Yes, it seems people seem to just want to move their living room into their cars, doesn't it?
 
  • #9
Moonbear said:
:rofl: Yes, it seems people seem to just want to move their living room into their cars, doesn't it?
And that's why there are so many wrecks, people forget that they're driving. Or should be driving and not applying makeup, reading (I know people that read books and newspapers while driving), talking on cell phones, smoking, eating (yeah, I'm guilty of that one, I've come close to getting in a wreck trying to keep my burger/taco/whatever from dripping on me). :redface:
 
  • #10
I've never had any trouble with eating while riding my bike.
 
  • #11
BicycleTree said:
No, I mean transmitting the siren across all radio frequencies. So the siren comes over your radio.
I'm not sure how easily that could be done relative to a single frequency, and it would probably meet with greater FCC resistance than having one dedicated frequency as an "emergency channel," such as is done with CB radios. If transmitting over all radio frequencies, it's also going to disrupt radios in houses that don't need to get out of the way! I'm sure the people who are already bothered by the sirens along the route to the hospital don't need yet another disturbance to their radio listening at home.

Any modification to the car is probably going to meet with resistance. It's the ambulances' problem and car companies aren't going to cooperate without a lot of incentive. Much better to put stuff on the ambulance than on the car.

But it's not just the problem of the ambulance. It's as much of a problem for the person hit by the ambulance as for the patient in the ambulance, or even you on your bike that the driver doesn't notice pedaling alongside them when they suddenly swerve to the side of the road when they notice the ambulance or fire truck bearing down on them at the last moment.

Another solution is just to make the siren louder, or to allow it to focus sound onto specific non-responsive cars (as I understand it this can be done).

Okay, you bike a lot, and surely you've been passed by fire trucks with sirens blaring with no metal, fiberglass or glass between you and that siren, right? Do you really think the sirens aren't loud enough? It's already deafening to a pedestrian or cyclist.

A side benefit of this, that I really hadn't considered before until reading that comment, may be in situations where an ambulance is entering a residential neighborhood at night. You want to approach with lights flashing, but sometimes they turn off the siren to avoid waking up the entire neighborhood at 3 a.m. if there's nobody on the streets. If it's a call that they can respond to a bit slower (broken leg type things), then they do try to do this (and you can see the flashing lights from quite a distance at night). In those situations, the ambulance could avoid turning on the siren, but still have a way that any drivers would have an extra alert of the approaching ambulance in case they were developing late-night tunnel vision while driving.
 
  • #12
Evo said:
And that's why there are so many wrecks, people forget that they're driving. Or should be driving and not applying makeup, reading (I know people that read books and newspapers while driving), talking on cell phones, smoking, eating (yeah, I'm guilty of that one, I've come close to getting in a wreck trying to keep my burger/taco/whatever from dripping on me). :redface:

I have to agree. I'd prefer that the cars just not be sound-proofed and that radios not be permitted to go above a maximum volume, along with enforcing reckless/distracted driving laws (not just going after cell phone users, but everyone who is doing something other than driving). I guess I just don't expect that to actually happen. The potential downside to something like an extra warning system is that it may lead to more recklessness as people allow it to be another substitute for paying attention to the road around them.
 
  • #13
If people are listening to the radio in their houses when the blaring siren goes past, it won't make any difference--they'll just be hearing the siren from two places, not a big difference. The only people it would make a difference to would be people listening to the radio in soundproof booths. There are not very many of those.

An "emergency channel" would entirely defeat the point. The point is to get the siren across to people who are listening to the radio in their cars, not people who are listening to the "emergency channel" in their cars.


Sound-focused sirens are probably the best idea. Focused sound could concentrate specifically on the area that the ambulance needed to have clear, in addition to a general diffuse siren that people could hear.
 
  • #14
You know, on a bicycle you can hear the sound of cars moving around you. You use your ears to find out what's around you.
 
  • #15
BicycleTree said:
If people are listening to the radio in their houses when the blaring siren goes past, it won't make any difference--they'll just be hearing the siren from two places, not a big difference. The only people it would make a difference to would be people listening to the radio in soundproof booths. There are not very many of those.

Um, in the houses, they are allowed to use soundproofing material to drown out the sirens, so no, it wouldn't have to disturb them to the extent having the radios all blare a siren would. I'm trying to stick within the realm of reality and what the general public might actually agree to.

An "emergency channel" would entirely defeat the point. The point is to get the siren across to people who are listening to the radio in their cars, not people who are listening to the "emergency channel" in their cars.
Okay, let me try this again...by an "emergency channel" I didn't mean for transmitting on the car radio, but for the external receiver to be tuned to that would display the warning, cut the radio, whatever it does. I don't think it would be useful for transmitting a message over a car radio because nobody would tune to that frequency on the radio (unless you're an ambulance chasing lawyer, perhaps :rolleyes:).

Sound-focused sirens are probably the best idea. Focused sound could concentrate specifically on the area that the ambulance needed to have clear, in addition to a general diffuse siren that people could hear.

I think you've missed the point. I'm talking about the vehicles that are out of sight range of the approaching emergency vehicle -- the ones coming from the intersecting road from both directions, perhaps with buildings obstructing the view; these are the vehicles that are unaware they need to slow down before they get to the intersection and need earlier warning. Besides, sirens already are pretty directional.
 
  • #16
BicycleTree said:
You know, on a bicycle you can hear the sound of cars moving around you. You use your ears to find out what's around you.

I do know that. That's half the point I've been making, that car manufacturers seem to be doing more and more to eliminate hearing as a viable means of detecting what's happening around you. There is also a deaf population that does not have advantage of this sense. The topic here is about motor vehicles with sound proofing and radios, not about bicycles or debating alternative modes of transportation. If you want to discuss alternative transportation, please do so in another thread.
 
  • #17
Moonbear said:
The potential downside to something like an extra warning system is that it may lead to more recklessness as people allow it to be another substitute for paying attention to the road around them.
It's also important to hear the siren and KNOW which direction it's coming from. If you see or hear some alert and don't know where the vehicle is coming from, how will you know what to do?

How about someone honking their horn at you to let you know you're about to hit them? Or the sound of screeching tires letting you know something's wrong and you need to assess what's happening. I've avoided a couple of collisions because of the sound of screeching tires.

There are too many reasons you need to hear what's going on around you when you drive.

I live in tornado country, trust me, you want to hear that siren when it goes off, it may be the only chance you have. They recently replaced the old siren on my street with one that will wake the dead. The one they had before couldn't be heard with the windows closed and the airconditioning on, which is the time of year that tornadoes occur. If you're driving, you want to hear that siren, once you're in it's path, it's a bit too late.
 
  • #18
Very few people use soundproofing to that extent in their houses. An ambulance-mounted radio transmitter is a perfectly good idea. Any modification to the cars as opposed to the ambulance is not going to happen without drawn-out legislation. But it's easy to mount a radio transmitter in an ambulance. When you get down to it, if making sure people can hear the ambulance is less important than making sure a very few people listening to the radio in soundproof rooms don't hear an annoying siren, then maybe everything is fine already. On the other hand, if you think the importance goes the other way, then we should put radio siren transmitters in ambulances.

If there are buildings in the way, then I suppose the ambulance could reflect focused sound off buildings to target spots around corners. But for the majority of cars, focused sound would work fine.
 
  • #19
I think you're just jealous that you didn't come up with the radio idea first.
 
  • #20
I think that the transmitter/receiver idea is a very good one. As Evo pointed out, directionality is important too. Maybe an ADF circuit should be included in the receiver so it can point to where the siren is.

BicycleTree, you seem to be totally ignoring the vast number of people, including me, who don't listen to the radio as well as the aforementioned deaf ones. Transmitting to an inert radio won't offer any visual cue.
 
Last edited:
  • #21
Evo said:
It's also important to hear the siren and KNOW which direction it's coming from. If you see or hear some alert and don't know where the vehicle is coming from, how will you know what to do?

Yep, I agree on that. Darn, I get sidetracked easily...that was what I was thinking about in my initial post about having it shut off or turn down the radio...eliminate the radio noise so you can hear the direction of the siren. Even with a car that's not well sound-proofed, I find sometimes I hear a faint siren and need to open the windows a crack to determine direction to decide if it's approaching me or traveling somewhere else. Since I work on a medical campus and am surrounded by hospitals, there are a number of directions emergency vehicles could be heading when I hear a siren.

How about someone honking their horn at you to let you know you're about to hit them? Or the sound of screeching tires letting you know something's wrong and you need to assess what's happening. I've avoided a couple of collisions because of the sound of screeching tires.

There are too many reasons you need to hear what's going on around you when you drive.

I agree. Just the other day, I was stopped waiting to make a left turn, and another car was stopped behind me, waiting, when a third car came along too fast and was not going to brake in time. Fortunately for the car behind me, who would have been sandwiched, I heard the tires start screeching and saw where the car was that wasn't going to stop, and I pulled straight forward to give the car behind me room to get out of the way and the third car more braking room.

The person in that SUV that was in the near collision with the fire truck had people stopped on the other side of the intersection honking their horns at him, and that didn't help either. If anything, it's more important to have auditory information if you're driving a large vehicle that restricts your visual range (those things really have huge blind spots). So, yeah, that's one reason I'd worry this idea might have the bad side effect of making people think they can stop paying attention, though, on the other hand, people are already not paying attention.


I live in tornado country, trust me, you want to hear that siren when it goes off, it may be the only chance you have. They recently replaced the old siren on my street with one that will wake the dead. The one they had before couldn't be heard with the windows closed and the airconditioning on, which is the time of year that tornadoes occur. If you're driving, you want to hear that siren, once you're in it's path, it's a bit too late.

Don't they have tornado radios? Ones that turn on like an alarm clock when the sirens go off? I thought I remembered one of my TX cousins mentioning something like that. If so, those must be tapped into a local frequency to go off at the right time (I have no idea how those work). If not, maybe a similar idea would work to transmit a signal from those towers with the warning sirens, to alert people in vehicles and who are asleep in their homes that there's a tornado warning they should know about and tune into listen to instructions. I know our tornado warning sirens here are too far away to wake me up if I'm asleep, even with the windows open. If the warning comes when I don't have the TV or radio on, I'd have no way to know. I also receive TV signal from two cities here, so I can be watching something from the other city and not be aware there are warnings for my local area. We may only get one warning a year, so I'm not overly worried, but nonetheless, if it happens while people are sleeping, or while they are listening to CDs instead of radio, being clued in that it's time to turn on the weather station would be a good thing.

So, I guess the warning system for emergency vehicles isn't going to be terribly useful, but maybe one for tornadoes would be?
 
  • #22
Danger said:
I think that the transmitter/receiver idea is a very good one. As Evo pointed out, directionality is important too. Maybe an ADF circuit should be included in the receiver so it can point to where the siren is.

BicycleTree, you seem to be totally ignoring the vast number of people, including me, who don't listen to the radio as well as the aforementioned deaf ones. Transmitting to an inert radio won't offer any visual cue.
Well, if you don't have the radio on, you probably can hear the siren anyway.
 
  • #23
Danger said:
I think that the transmitter/receiver idea is a very good one. As Evo pointed out, directionality is important too. Maybe an ADF circuit should be included in the receiver so it can point to where the siren is.

Is that something that's possible? See, what I'm presenting here is just a vague idea that I only just hatched up after reading the radio thread. I wouldn't have shared it if I thought I knew enough to build it and make a profit! :biggrin:

BicycleTree, you seem to be totally ignoring the vast number of people, including me, who don't listen to the radio as well as the aforementioned deaf ones. Transmitting to an inert radio won't offer any visual cue.

He's also ignoring how formidable the FCC can be when it comes to transmitting over even one frequency let alone a spectrum of frequencies. It also won't help the vast majority of people who are playing CDs or MP3s or sat radio rather than using the FM dial. If people will complain about having a blinking light added to their car, they sure as heck are going to gripe and lobby to block implementation of something that would interfere with listening to the radio in their own homes.
 
  • #24
BicycleTree said:
Well, if you don't have the radio on, you probably can hear the siren anyway.

Please go back to the original post and re-read.
 
  • #25
Yes, the radio is only one of a number of contributing factors. But without it, you're probably back in the safe audibility zone.
 
  • #26
I think the FCC might make an exception for short-range transmitters on ambulances. It's more likely than car manufacturers and ambulance companies working together to create a warning system that mainly only profits one of them and is a cost mainly to the other.
 
  • #27
Moonbear said:
Is that something that's possible? See, what I'm presenting here is just a vague idea that I only just hatched up after reading the radio thread. I wouldn't have shared it if I thought I knew enough to build it and make a profit! :biggrin:
Entirely possible. ADF stands for 'Automatic Direction Finder' and is standard aircraft equipment. You've also probably seen a smaller version on cop or spy shows, where they have a tracer bug on a car or something. One potential problem that I can foresee is that a lot of buildings incorporate material and/or equipment that blocks radio transmissions. Repeater units might be needed at some intersections, which would invalidate the ADF. I still think that the whole thing is a good idea. Maybe someone in your school's Communications dept. (if you have one) could look into it.
 
  • #28
I remember reading something a few years ago about a siren sound that was specially designed so that people could tell what direction it was coming from. I think it sounded more static-y for more noise information, and it was tested in Great Britain. I don't know what became of that.
 
  • #29
Danger said:
Entirely possible. ADF stands for 'Automatic Direction Finder' and is standard aircraft equipment. You've also probably seen a smaller version on cop or spy shows, where they have a tracer bug on a car or something. One potential problem that I can foresee is that a lot of buildings incorporate material and/or equipment that blocks radio transmissions. Repeater units might be needed at some intersections, which would invalidate the ADF. I still think that the whole thing is a good idea. Maybe someone in your school's Communications dept. (if you have one) could look into it.

Hmm...yeah, that would be a problem with buildings between the emergency vehicle and target vehicle if the building material was adequate to block the transmission of the signal. On the other hand, that's less likely to be a problem outside of cities, and cities are where they're already incorporating things like traffic signal switches controlled from emergency vehicles, and maybe could be convinced that the repeaters at intersections are cheaper than repairing emergency vehicles after collisions.

I don't think, even if someone had a viable design, that it would be immediately embraced by car manufacturers (they might not want to admit their sound-proof vehicles present a safety hazard, or if they are forced to admit it, it's cheaper to remove some sound-proofing than add on a new component). But maybe as a custom option for those who are deaf, or market it in larger vehicles not as something to address a sound-proofing problem, but the known need for a longer stopping distance.

I guess the overall impression I'm getting as I discuss this more is that it may sound like a good idea, may even be something that can be designed and installed, but it's probably not marketable. *sigh* The downfall of many good ideas. :rolleyes:
 
  • #30
It's really not a very significant problem anyway.
 
  • #31
and maybe could be convinced that the repeaters at intersections are cheaper than repairing emergency vehicles after collisions.
You could use repeaters for focused sound, too, without having to install stuff in the cars.
 
  • #32
BicycleTree said:
You could use repeaters for focused sound, too, without having to install stuff in the cars.

Not that it solves the problem of soundproofed cars, but that does sound like a good idea outside of the soundproofing issue. It would help let cars approaching the intersection know that yes, this is the intersection that fire truck is about to come barrelling through! Better than just changing the light to red, which doesn't necessarily indicate an emergency vehicle is coming through. Definitely would be useful in an area such as where I drive frequently when there is a lot of emergency vehicle traffic en route to the hospital.
 
  • #33
BicycleTree said:
It's really not a very significant problem anyway.

What do you mean it's not a "significant" problem? Response time is slowed every time an emergency vehicle entering an intersection has to slow down for a vehicle that has not stopped for the siren, and worse when there is an actual collision. The other part of the issue here was the one more generally about vehicles being overly sound-proofed, not just with regard to hearing emergency vehicles, but all warning signs they need to be aware of. This makes the roads unsafe for everyone.
 
  • #34
Well, the idea behind focused sound would be that you could make it much louder without bothering other people. So if a car appeared not to be responding, you could focus twenty more decibels of siren on that car, and nobody's windows would break (except maybe that car's). At an intersection where the ambulance can't see which particular cars might be trouble, you could beam sound in both directions at the intersection just along the road so that only approaching cars would hear the extra noise. Louder without being a nuisance would be the objective in both cases.

You could also add an extra light beside stoplights. Red, orange, green, and then hanging beside it in another box, searchlight-intensity red.
 
  • #35
BicycleTree said:
Well, the idea behind focused sound would be that you could make it much louder without bothering other people.
Is there no way to get it into your head that it doesn't matter how much you focus your sound—a deaf person can't hear it!
 

Similar threads

  • General Discussion
Replies
11
Views
901
Replies
7
Views
736
  • Electrical Engineering
Replies
20
Views
536
Replies
13
Views
1K
  • General Discussion
Replies
19
Views
3K
  • Introductory Physics Homework Help
Replies
9
Views
3K
Replies
2
Views
889
Replies
4
Views
2K
  • General Discussion
2
Replies
40
Views
6K
Back
Top