Tuesday, January 31, 2006


I was on a bike ride this weekend. I was sitting at an intersection waiting for the light to turn green. As I was waiting, a big fire truck turned into the road to my left and started heading toward the intersection with its siren wailing and all the lights flashing.

As the fire truck approached it got louder and louder. It became so loud that I reached up to hold my ears. The amount of noise coming out of the siren was deafening. The light turned green, and everyone in my lane sat there waiting for the firetruck to go through the intersection.

However, in the lane facing us, there were cars that had completely missed the firetruck's light show and siren. When the traffic light turned green, one car shot right into the intersection without a care in the world and nearly ran into the fire truck.

This is amazing if you think about it, because by this point I could nearly feel the pressure waves of sound coming from that siren. I have no idea what the decibel rating of a modern siren is, but it must be huge. Which makes sense, given that the sound of the siren has to penetrate the cabin of modern, sound-proof automobiles and overpower the sound of unmuffled Harleys.

But the fact that I was having to hold my ears to avoid deafness, while cars were moving into the intesection oblivious to the siren's sound, shows that we have reached the end of siren technology. It is time to think of a better solution. Sirens cannot get any lounder without causing local earthquakes. Sound waves simply are not the answer.

In 20 years, when robots are doing all the driving, this will be a moot point. Emergency vehicles will send wireless messages to robot drivers telling them to move out of the way seamlessly. The interesting question is, what do we do in the meantime to create an inexpensive, better solution to the problem that sirens are trying to solve?



At 4:42 PM, Anonymous Massimo Lorenzi said...

to replace or just help sirens doing their work with a minium upgrade cost I think that emergency vehicles could be allowed to have sirens coupled with radio transmitters; the radio transmitter could broadcast the siren sound, or any compliant message, overimposing his signal on car stereos tuned in normal FM-AM stations so that drivers would be aware of incoming emergency vehicles.
As a matter of fact many of us just miss the siren cause we listen to our car stereo at too high volume.
This kind of siren would also be able to advice drivers much faster and farther and with much more "cornering buildings" skills than actual models.
By the way this would work only for drivers actually listening to the radio but with a minumum effort future car stereos could be built capable of recognising the siren signal and tune in whatever you are listening to(quite like some nowadays stereos that decrease volume on incoming cell calls).
In the future this tecnique could just switch medium going on wi-fi or whatever will be standard for car communications.
I admit that this kind of radio hijacking sound quite intrusive but I'm good willed to give out some personal "listening" freedom to increase pubblic security.

I find "HowStuffWorks" one of the most interesting site around!


At 5:34 AM, Blogger Roland said...

Wow, that's an absolutely awesome idea! You should sell it.

At 1:56 PM, Anonymous Anonymous said...

Interesting concept, though one only wonders how many people would find a way to disable it after their favourite song gets interuppted by the switch to the emergency broadcast for the fifth time...

One would still need sirens. I don't see manual driving being outlawed in the near future... too many people enjoy driving (come on... why else would you need a convertable porsche? I mean, it snows here six months a year and people still buy those things!) and to outlaw it would cause massive outcry. And someone driving manually, in a car with a broken/stolen/bypassed radio would still need to be informed...

This of course totally ignores the yahoo on the harley wearing the video glasses or whatever passes for an ipod twenty years down the road... or even someone on a conventional bicycle, because we all know how attentive they are... certainly manic bike courriers will still be around then (human or robotic... though I forsee robotic bike courriers being programmed to be even more reckless than humans, and faster, and eminently more replaceable when they do get run over)

At 8:29 PM, Blogger Roland said...

I don't know if manual driving would be banned, at least not for quite a while. After all, there are still plenty of old cars around. And who did have new cars would probably prefer automatic driving on their commute anyway.

At 9:05 AM, Anonymous Massimo Lorenzi said...

Anonymous said:
"Interesting concept, though one only wonders how many people would find a way to disable it after their favourite song gets interuppted by the switch to the emergency broadcast for the fifth time..."
There will be no switch at all..so no way to disable it..
The siren signal will just be stronger than the AM-FM one, so it will cover the second one on the whole AM-FM band just cause it is stronger than the other.

Roland said:
"Wow, that's an absolutely awesome idea! You should sell it."
Would be great if I could.

At 3:51 AM, Anonymous Anonymous said...

check out this news item from nz relating to emergency sirens


At 11:33 AM, Anonymous Anonymous said...

Here's the world's loudest siren:


4-mile range.

At 10:14 AM, Anonymous Anonymous said...

How does the car-radio siren substitute help you, on your bike? How does it help the pedestrian know not to cross the road when there's an emergency vehicle? Many times I have only been alerted to their presence by the siren, the intersection itself usually holds your attention rather than what's coming beyond it.

It also takes the siren out of the hands of a single entity, which can easily be made redundant to deal with mechanical failures; by putting a single siren in tens of thousands of cars you're putting responsibility on many devices that have a high reliability, but not perfect; devices that for economic reasons probably are not going to be redundant. Equipping a fire truck with 2 sirens is cheap; equipping five hundred million cars with two siren recievers is not.

There is also going to be widespread resistance to the costs of retrofitting older vehicles.

This seems like one of those instances where the simplest solution is probably the best one. In these cases, I expect that the "sadtech solution" is probably going to be the one that endures.

At 4:49 PM, Anonymous Anonymous said...

I'm not a very smart person, but I think this might be useful.

Why not put the 'responsibility' of notifying drivers on the one thing they'd be paying attention to... the stop light?

Think of a small receiver connected to the stoplight. A similar transponder will be triggered 'on' whenever the emergency vehicle turns on that air-raid siren. Once the emergency vehicle gets with say, 100yds, the signal from the siren-box clicks a relay in the stoplight transformer, and *ding!* the stoplight starts flashing red, and possibly kicks on a small strobe underneath. People see that the redlight is flashing, and see the strobe blinking, and know to wait until the emergency vehicle has passed.

It seems like it would require minimal effort and maintenance to keep going, and could even be somehow stuck into an internal switching network connected to a GPS (to 'automate' empty lanes for emergency vehicles).

I'm sure there's a lot of ways to shoot my idea down (pranksters with signal generators) but anything's better than another, louder chrome siren on the top of a vehicle that still won't be heard over the cacophony of the Harley Bros. on my right and "12KW Subwoofer Van" man on my left.


At 11:33 AM, Anonymous Wesley Snyder said...

I am an electrical engineering professor (so I know the technology is possible), and I was also a practicing paramedic in North Carolina and had the opportunity personally to observe drivers who are incapable of noticing sirens, ambulances, fire trucks, etc. For several years, I have been advocating that all audio amplifiers sold for installation in automobiles be equipped with a simple radio receiver that simply mutes the amplifier whenever the transmitter (on board the emergency vehicle) is near. It wouldn't fix the entire problem, but would be a huge improvement. We could instrument the traffic light too, but just shutting off the in-car sound would do the job. Only on newly manufacured amplifiers only a few cents per amp. This COULD be implemented by individual state legislatures, without waiting for congress. Perhaps North Carolina is the place to start?

At 7:28 PM, Anonymous Brian Eliason said...

It's called Opticom. Special frequency white strobes on the emergency vehicle trigger the traffic signal to go to red for all directions except for the approaching strobe. It works, but, alas, NOTHING can override the inattentiveness of some drivers. I have personally seen people run red lights only to drive into the side of fire engines the size of a small house with lights, sirens, air horns, Red paint, yellow paint, Opticom working, etc...Anything you add to someone's car will be defeated by some portion of the motoring geniuses on the road today. After over 20 years in the fire service, I believe that the current systems work well, but the emergency vehicle operator must learn to be the most defensive driver on the face of the earth.

At 4:42 PM, Anonymous Anonymous said...

I am a firefighter (also a technology buff, that's how I came across this page), and I have an idea that might not have run across any of your minds up until this point: Watch the road. Stop texting, emailing, talking on phones, listening to your ipods, watching your drop down dvd screens, and do what the license in your wallet gives you the lawful ability to do: drive. Please realize that my frustration in this situation only comes from the number of comrades who have fallen thanks to someone not paying attention causing the crash of a fire truck. Fire truck accidents are doubly tragic given that as firefighters in emergency response, we are on our way to do a civic duty for someone else undergoing their own tragic time. Now, thanks to an irresponsible driver, the firefighters are undergoing a tragedy of their own and the person they were attempting to respond to and protect, is left without an emergency response team. Unfortunately, the only way we firefighters currently have to effectively do our jobs is with those very large, red, loud, vehicles which some day might happen to be transporting the public service officer who saves your life. So, next time you hop in your car, realize the only thing that this current day and age has to provide us with is our own eyes and ears. Pay attention and save both your own life and the life of one of my comrades.

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At 8:22 PM, Blogger Clive said...

Driver awareness is probably the biggest problem: dealing with the unpredictable is always a tough call for a driver, so maybe dealing with emergency vehicles should be in all driver training curriculum. That is, how to deal with them mobile, and when parked. Becuase I used to drive fire trucks, I always approach intersections looking for the unusual, but I see other drivers just sail through, as if the green light is going to protect them from nutters.

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