Originally Posted by
chaadster
So, while you're free to scoff at the fact that 99.9% of road users-- cars, motorcycles, RVs, trucks, and snowmobiles-- are expected to know, recognize, and employ when necessary, the 90º left arm gesture to signal a right turn, hopefully you'll forgive me for thinking there is a smarter way to share the road.
You have been provided several examples of states that allow both types of signals. The final authority on all things vehicle related is the National Committee on Uniform Traffic Laws and Ordinances. They state the following with regard to hand turn signals:
11-606.Method of giving hand-and-arm signals
All signals herein required given by hand and arm shall be given from the left side of the vehicle in the following manner and such signals shall indicate as follows:
Left turn.Hand and arm extended horizontally.
Right turn.Hand and arm extended upward.
Stop or decrease speed.Hand and arm extended downward.
Notwithstanding the foregoing provisions, a person operating a bicycle may give a right turn signal by extending the right hand and arm horizontally and to the right side of the bicycle.
This is the basis for state laws permitting right turns allowing for the use of the right hand while riding a bicycle. You use them in a car for obvious reasons and you can't use them on a motorcycle because of the controls but for a bicycle they make perfect sense and, in my experience, motorist, bicyclist and pedestrians aren't confused by them. Additionally, in my experience, using the right hand for right turn signals is less awkward for making a right turn.
As for people actually knowing that a raised left hand means a right turn,
here's what your state LAB has to say about that
According to a study by
Drury & Pietraszewski, the bent left arm signal was correctly perceived by 65% of following drivers, but the straight right arm signal was perceived correctly by 78%.
What's really sad about the Drury study is that it was done in 1979 when far more people may have been exposed to cars that didn't have turn signals.