Inaudible sirens and car accidents

[JasonC]

I agree with you, they should put mechanical sirens back on emergency vehicles, today on my way home from school, I was able to hear a fire truck,with a federal Q siren on it, coming down the road, it was about 1/2 a mile to a mile away when I first heard it, but when a police car with an electronic siren goes by, I can`t hear until it is about 2 blocks away.

You can't put a Q siren on anything smaller than large fire trucks, it would completely swamp the electrical system.

Frankly, cars are just to insulated today for electronic sirens to work well. That's the biggest problem. But honestly, it's up to the emergency vehicle driver to realize this and drive with due regard. When I used to be a volunteer firefighter and would drive the trucks, I basically assumed other cars couldn't hear my sirens, and drove like it. You really have to stop at intersections and look around.

People don't realize when you have your lights and sirens on, you are asking drivers for the right of way, it's not just given to you. Unless the other driver breaks traffic laws or is parked, when a collision happens with an emergency vehicle, it's usually their fault.

Just remember to slow down and be cautious. Remember, it's not your emergency, and it's not worth your life. You aren't' going to be any good to the patient or whoever if you wreck on the way to the scene (and in fact you'll hamper further response).

There are several other mechanical sirens made besides the Q (Timberwolf siren, B&M siro-drift, etc). Unfortunately on smaller vehicles, electronic is still the only option.

[Jpressman8]

There are electrical options that will make it possible for mechanical sirens on a squad car like heavy duty alternators or dual alternator options, but I would think room and placement of the siren would be more of a problem. You can't mount them on the roof due to risk of hearing damage. The only option is bumper mounting which is most likely a problem with the more modern cars. The fire engines here in Green township have electro mechanical sirens and what I call a get the **** out of the way air horns on them. They blow these air horns on approach of an intersection. If you don't hear them there is something wrong with you. The station is about a half mile from the house and I can hear them when they leave the station. The ambulance and squad cars are the ones that are hard to hear. Those are electronic.

[Henry455]

You can't put a Q siren on anything smaller than large fire trucks, it would completely swamp the electrical system.



There are several other mechanical sirens made besides the Q (Timberwolf siren, B&M siro-drift, etc). Unfortunately on smaller vehicles, electronic is still the only option.[/quote]

I politely disagree concerning electro-mechanical sirens, if the electrical system is designed right, there would be no reason they could not be used on smaller vehicles. Remember, back in the 40's, 50's and 60's almost ALL emergency vehicles large and small had mechanical sirens. I know this is far fetched but look at this video: http://www.youtube.com/watch?v=FRuZUGnSb2k

[JasonC]

The air horns on fire trucks are Grover "Stuttertone" air horns.

As far as the electrical system goes, large fire trucks usually have dual 300 amp alternators and 4 batteries to provide power (where Police cars only have 100 or 160 amp alternators). Q sirens draw about 300 amps when spooling up and over 100 amps peaked. For one, there isn't room under the hood of smaller vehicles to add additional alternators and batteries. Also, the current draw of a Q would dip the voltage so low it would damage many of the electronics inside a smaller vehicle (laptops, MDT's, camera systems, etc).

Vehicles back in the day did have mechanical sirens, but they also didn't have all the electrically powered components of todays vehicles. Also, the smaller emergency vehicles back in the day used smaller mechanical sirens. The smaller V series sirens were one example, as they were made to interface to small cars and trucks and didn't require much electrical power. There's a video floating around on Youtube of a fire truck responding, and every time the Q spools up, the wail of the electronic siren slows down considerable because of current draw.

Smaller electromechanical sirens such as the Timberwolf siren are designed to be wired into smaller vehicles as they draw only a fraction of the power of a Q. Also, air horn kits are a very good alternative as they can be blasted when needed, and also solves much of the problem of excess noise pollution.

[Jpressman8]

Jason , Fire Engines use a 24 volt system don't they?

[Henry455]

Still disagree Jason, many pick-up's and 3/4-1 ton chassis cabs come with dual battery trays although only one battery might be installed and you could get dual alternators on Ford diesel pick-ups. My nephews new Suburban has provisions for dual batteries although because it gas powered it only has one installed.

When I was a member of a volunteer rescue squad back in the 60's and 70's most of our units were Chevrolet or GMC panel trucks, Suburban with no side windows. We ran a Q, a Sireno 100 watt siren, 2- 3 bulb beacon ray type lights, a SolarRay, 2 par 36 cowl lights and 2 pancake lights, plus 1 VHF and 1 low-band radio and a scanner . We did use 2 batteries and a 120 amp Leece-Neville alternator but they were normal size pick-up batteries. We had 6 units and the smallest siren we ran was of the 8" type, C class Federals or B & M's.

I have a Q plus some other mechanical sirens and while they do have a inrush current surge that lasts a few seconds, mine is not near 300 amps, closer to 200.
Even if it was, my 2 group 65 batteries have 1100 cranking amps (not CCA) EACH. If you have a Q that is drawing 300 amps, you have a wiring problem, bad brushes or bad motor bearings.

Have not seen the video but I suspect there is something wrong with the installation of that Q, the Q itself or the vehicles electrical system.

[Jim_Ferer]

I grew up in that era. Ambulances and police cars didn't use Q sirens for reasons of space and current draw. There were companies like Sireno, Dietz, and Federal itself making sirens for these uses. IMO, when these sirens were mounted under a hood they weren't better than the electronics in use now.

A lot of electronic sirens aren't selected, installed, or used for maximum effectiveness. I'd bet most police cars you find have one speaker instead of two, mounted so as to muffle the sound to the maximum. Hell, the F.D.N.Y. uses the old 58 watt sirens to avoid noise pollution, at least in Manhattan. Going with two speakers would be an improvement just to start, and there's other technology and tricks out there like the Rumbler, and just plain more watts. I'd like to make a killer system with a 200 watt siren and Martinshorns to clear the intersections; I bet it would be awesome.

This is the direction to go in (plus Jason's points) because the world isn't going back to mechanical sirens. It just isn't ever going to happen, whatever the merits of the situation are. We're into the art of the possible, in other words.

[kx250rider]

People don't realize when you have your lights and sirens on, you are asking drivers for the right of way, it's not just given to you. Unless the other driver breaks traffic laws or is parked, when a collision happens with an emergency vehicle, it's usually their fault.

True in many, many cases. But in the case I witnessed, it's a blind corner with brightly-lighted businesses on all corners. So it's a perfect storm for an emergency vehicle to be unseen/unheard, as the lights are drowned out by commercial signs and lights, and the sirens can't be heard until you're square in front of the oncoming vehicle. I watched the officer make a cautious "hollywood stop", but he was behind the limit line, and out of view of the little black Mitsubishi who was coming at 45mph with a green light. Just no time for either driver; no matter of experience and skill, to do anything. A real siren would have prevented that one, and if this collision costs the county $500,000, which it most probably will, that would pay to equip the entire county fleet with Model Qs, and the problem of swamped electrical could be solved with a couple of dedicated batteries with anti-backflow diodes and an RV alternator. Then the next $500,000 saved by NOT HAVING the next accident with a quiet siren, could go to emergency vehicle traffic signal override, which is even better. That way, an approaching emergency vehicle could trigger all lights to go red, and stop all traffic ahead.

Charles

[JasonC]

If it was a highly obstructed intersection, the officer should have crawled through it (I've done it several times where traffic was immense).


Even if you have a Q, it still doesn't solve the problem. The decibel rating of a Q is still the SAME as a 200 watt siren (even though SPL may be higher). People still can't hear you or know you are there...this is especially true at high speeds (which sounds like the case you are describing Charles). Those incidents are the most common at speed emergency vehicle collisions as vehicles on the other lanes may have stopped and the unknowing driver proceeds through the green light at speed not knowing there is an emergency vehicle. In that case, visual warning is MUCH more effective at a distance than a siren ever could be.

Electrical differences aside (even if you were able to rig up several batteries and high output alternators into a police cruiser, there would be no room to do so), there's a reason why you see firefighters with those headsets on in large trucks. The noise is deafening. For police work, which requires a lot of radio chatter, its just impractical. And you can forget about anything but the largest ambulances where patient care is involved. There's also no place to put a Q on a cruiser.


IMO, putting Q sirens on everything just shifts the problems around and creates new ones. Cars keep getting more insulated and sound systems drown out the noise, which makes them more ineffective.

My vote is for more pre-emption systems and the use of air horns (which many ambulances have started using since their electrical systems are already maxed out..thats with dual 145 or 160amp alternators and 3 batteries).

Sirens have severe limitations when it comes to vehicular warning in the modern world, the use of more modern technology has more benefits.

[Jim_Ferer]

There's been radio sirensa proposed before - a 200 milliwatt transmitter combined with receivers in cars. I don't know how well that would work. It would be more practical now with current technology, and it would take perhaps three years or so to implement in existing cars and to add to new ones.

<wonders how to get a Q into a 2010 Impala>