Hi BikeForums. I just mounted a bike horn on my handlebars that I bought from ebay for $5. It claims to have 115db and it also features a blinkie. I bought it because I got hit at an intersection (she had the stop, I did not have a stop sign). Now I beep at people that I'm not sure if they are going to stop at intersections. Even though cyclists aren't trained to do this it is necessary, because drivers are idiots. Here's a demo I made: https://www.youtube.com/watch?v=B4CMcx7Oi4c

Let us know if drivers seem to be actually responding to it. One or two of those sounded loud enough to maybe be heard.

FYI red lights up front are technically illegal in many jurisdictions, but I doubt it would be enforced.

I use the first one, and yes I believe people are responsive. I used to get cut off a lot because drivers "didn't see me". I reply in the same dumbfounded way "you didn't exactly come to a complete stop" uh-duh. This thing is like: hey mfer pay attention to me! without actually having to shout that. Sometimes I just tap the putton twice and wave at the driver coming out of a driveway.

I seriously doubt that the horn has an output of 115db. This reference shows the levels for various sounds. https://www.gcaudio.com/resources/howtos/loudness.html As you can see, 115db is equivalent to sand blasting or a loud rock concert; it's also 5db higher than a power saw at 3 feet. My impression is that the horn is not quite that loud. N.B. if it is that loud, please note the cumulative exposure to 15 minutes of such sound in any day will lead to permanent hearing loss. That's the standard on which the OSHA regulations are based.

The basic problem is that sound insulation in the standard car, with windows sealed, air conditioner and radio on will make even a 115db horn inaudible. The NYC Fire Department kept making sirens louder because motorists were not getting out of the way. By the late 1960's the sirens had become so loud that firemen were going deaf and cars would still not move out of the way. I was taking an engineering course in sound and acoustics at the time. The professor arranged for us to measure sound levels for different sirens on the fire trucks, on the street and in cars. We concluded that the motorists in their cocoons could not hear the sirens and that the firemen had plenty of cause for going deaf. I believe that Detroit's penchant for removing the driver from road sounds stemmed from a Rolls-Royce advertisement at that time. The ad proclaimed that at 60 mph the only sound a Rolls-Royce driver heard was the sound of the [mechanical] clock.

I don't have a meter, but when I pressed the button in my room I could actually feel my eardrums moving. It may sound more electronic than a car horn, but it is loud enough to get noticed.

When they rate those things 115 DB, they do it by cramming the sound pressure meter right up hard against the buzzer.

I beeped my Airzound one time in my garage, the bike was facing out the garage door at the time, and I beeped it for like 1/4 of a second. My ears were ringing for about half an hour afterwards. It's actually not bad outside on the roads (it doesn't hurt my ears) but I know that people in loud cars with the windows rolled up can hear it even when they're a second or two down the road from me after passing too close.

Your probably right about holding it right up to the buzzer. The sound is much higher in an enclosed room. It's probably on par with airzound in terms of sound output, but I don't have one to compare it to. I will have to find someone with airzound and we will have a sound-off! I definitely like the size and profile of it better than airzound.

Nothing beats AirZound with oversized bottle at 90psi It's louder than car horns.

AirZound: but I have found that at intersections I just yield the right of way, so a horn for me is not all that useful. Occasionally I will ride a MUP then the AirZound is to loud in my opinion, but to wake up cars, it serves well.

By intersections I am referring to me having the right of way. I am also referring to people pulling out of driveways and making right turns on red into your path. This happens quite frequently to me.

Airzound saved me numerous times from getting hooked by a turning car. It's so freaking loud that people just hit breaks when they hear it. That Chinese beepy thing sounds like a toy laser pistol. No way that's over 100dB. It got even better results with a larger bottle and 90psi

I'm going to Queens.... you better bring it!!

I never leave home without it