If you're willing to do wiring and deal with a 12V battery do what I did and get a FIAMM 120dB car horn. From my experience people think that they are going to get hit from their blindspot, so they quickly shoulder check to see where the horn is coming from. Then they see me and react. I personally think this is better than an AirZound. Motorists have a tendency to filter out sounds that aren't horns so they can focus on the road (which isn't necessarily a bad thing on their part, but it's why whistles and bells don't work very well. Drivers think the sound is coming from the side walk for someone else.) I've just personally found that people take my horn more seriously. If an people in your area take the AirZound seriously then great! It saves you the hassle of making/maintaining electronics, but it's just an option to consider.