It is an issue we have discussed before: why are hand signals for cyclists so dumb and counter-intuitive? I noted earlier:
Very few cyclists bother to signal and there isn't much point to it, because very few drivers bother to pay attention to them or even understand them. Hand signals that cyclists are taught are derived from hand signals designed for drivers, who can only use their left arm.
Others note that using the left arm for all signals makes some sense; that's the side where the cars usually are, and the right hand is on the front brake, the one cyclists give priority to. But in fact, as in most cycling matters, we should learn from the Dutch and the Danes, who just point where they are going, using their right arm to go right.
Even Yvonne Bambrick, who has written the definitive Urban Cycling Survival Guide, is equivocal about this, showing this drawing and writing "to indicate a right turn there are two options: extend your left arm with your elbow bent and your forearm and hand pointed up, or extend your right arm out to the side."
Peter Cheney of the Globe and Mail picks up the issue, saying "It’s time for the old-school bicycle signal to die."
The best forms of communication are clear and unequivocal – such as an arrow that points in the direction you need to go. Using one arm to indicate two different turn directions plus stopping is anything but clear and unequivocal. Some drivers even confuse the raised left arm bicycle signal with the bras d’honneur (a gesture also known as the “Iberian slap,” or “Up yours!”)
Cheney proposes that we keep it simple and just point where we want to go. He rejects all the computerized add-on smart phone driven high tech solutions, many of which we have shown on TreeHugger.
As history has shown, the most successful designs are as simple as possible. So let’s forget all the electronics and go with my suggestion – use the arm on the side you’re turning toward, and point to where you’re going. You’ve probably heard of the KISS (Keep it Simple, Stupid) principle. This is KISS at its finest.
He's right. Let's end this confusion.