Average cyclists-and motorist-DON'T USE OR KNOW FORMAL HAND SIGNALS!
I'm old-61- I vaguely remember car stop/slow hand signal- left hand out window pointing down-about 30 degrees or so relative to perpendicular(I think- haven't used them in 45 years). Don't know what bike signals are-perhaps the same??- but since I don't know it-and 95% of cars bikes don't- pointless to use it.
I do know how to yell- SLOWING DOWN
I take some of that back-I do use the "turning left signal"-pointing left- when I'm turing left-so I guess I do use one signal-always very carefully-some car mirror might take my arm off
Yeah hand signals are dead-can't say I have every seen anyone-other than my own left turn-use them-not in 45 years.
Charlie