A company I worked for put them on all their vehicles one year to try and cut down on deer damage to our trucks. (About 45 vehicles or so)
Deer collisions went up immediately. At best they didn't work, at worst it was actively spooking them... either way they were removed shortly thereafter and the incident rates started dropping soon after that.
I wonder if this isn't a different cause and effect scenario. If everyone in the company knew about the deer horns and believed them to work, they likely wouldn't be taking the precautions they normally did.
Of course they don't work, but I'm wondering if the placebo effect is what caused the accident rate to go up. Or an increase in deer populations that year, or land development, or etc.
But yes, they don't work.
I would suspect that they really are counterproductive. Deer standing peacefully beside a road aren't a problem, deer running across a road to get away from a noise are.
I think it was more a matter of timing. It was in the fall around hunting season when more people are out running around in the bush and deer are on the move.
The whistles were our safety officers idea. The rest of us pretty much knew they were crap. (Or at least some of us did) The safety guy wasn't too sure either but figured they were cheap enough to at least give them a shot.
It didn't help matters that we were operating in an area with a very dense population of deer either. I've personally counted over 80 standing in a field by a road.
This is my understanding.
If there's an animal grazing on the side of the road as you approach, then at best the whistle is just going to startle them, and they could go in any direction, including into your path.
Ya, deer are not smart. I've had deer literally run towards me and into the side of my semi truck in an attempt to "get away." I saw it coming from about a quarter mile away, and it just kept running towards me. I even blew the horn a few times. I was basically at a stop when it bumped into me. (It survived, but probably was feeling very stupid later.) And this was still during daylight hours. I've also had one trip over the hood of my car while stopped.
I can only assume wherever they think is a safe spot when they panic they'll potentially bolt towards it, despite anything or anyone in the way.
They don't really work.
Is the whistle louder than the sound of your vehicle and the road?
Is that sound going to reach the deer before it's too late? What about when the wind is blowing in the other direction?One of the predominant frequencies of the whistles, 12 kHz is clearly outside the best frequency of hearing of the deer. The average sound pressure level at 3.3 kHz was determined to be around 70 dB re 20 uPa when the device was bumper-mounted at 40 mph and was totally lost to the road noise produced by the car since it falls within the range of car noise
I wonder if you can just blast that over speakers to get around the loudness issue?
Driving on the highway, at speed, will put out at least 75 dBs.
80 is generally the line drawn when you're causing hearing damage in humans. If you're blasting out the sound to go over the sound of the vehicle, you are causing other issues.
Edit:
I probably should've re-linked the article I posted earlier in the branch, and thrown in a quote with one of the example findings:
This would require signal strength of greater than 289 dB just for the animal to hear the sound.
You just put your lips together and blow.
If a large and loud fast moving object with bright headlights isn't spooking them then a faint whistle definitely will
They definitely do not.
Ran into a herd this summer with one attached to the front of our car. Did not seem to drive them any other way than into my car.
The same happened to my friend. I told them it was because they mounted the deer whistle backwards.
I think they considered it for like half a second before cussing me out.
I know one neighbor that has these festooned all over his minivan and has hit at least half a dozen deer in the last couple years, that I know about. Nobody else that I'm familiar with has this terrible of a track record . But then again, I've driven with him and he doesn't look farther down the road than the end of his hood.
The trick to avoiding deer is to never look at the deer you can see; it's the ones on the other side of the road that are trying to get over to the visible ones that you have to worry about.
Looking ahead, and recognizing when deer are out (usually around twilight hours), and slowing down are the things you can do to most easily avoid them.
But try telling some people to slow down and you'll get shot or otherwise ran over.
