destro713, I have actually installed a moped horn on a bike. Most moped horns are AC but DC can also be found on the market and the latter is needed when powering the horn from batteries. My mounted horn runs off 6V that I get from 5 AA rechargeable batteries. I also have another 6-12 V horn that is equally or not more loud at 6 V as my mounted horn. Anyway, I thought that it could be useful for you to know of this option of being like a moped. The loud signal is much more effective than a bell when dealing with motorized vehicles.

P.S. That intersection looks quite OK compared to what I've experienced in some other cities.