I'm not going to watch the video linked in sibling comments right now, but "pulsing loud static" is a pretty common alternative to beeping around me; especially in the big citie. Kind of a big shush shush noise: sometimes it sounds a little like hydraulics working which is fine because if you hear those, something big is happening and you should pay attention.
Anyway, the real nice thing is it's loud and attention catching near the source, but it seems to disipate faster than beeps, so you don't really hear it when it's not relevant.
I'm not going to watch the video linked in sibling comments right now, but "pulsing loud static" is a pretty common alternative to beeping around me; especially in the big citie. Kind of a big shush shush noise: sometimes it sounds a little like hydraulics working which is fine because if you hear those, something big is happening and you should pay attention.
Anyway, the real nice thing is it's loud and attention catching near the source, but it seems to disipate faster than beeps, so you don't really hear it when it's not relevant.