An interesting article from the Missouri Bicycle Federation:

What's the best way to signal right turns?
Monday, September 20, 2004
Some bicyclists signal right turns by raising their left hand to the square, others by extending their right hand.

Is one way or the other better for communicating to other cyclists and drivers? The Santa Clara Bicycle Coalition summarizes some interesting research into the matter:

What's the safest way to signal that you're turning right? According to a 1979 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%. Not only is it safer, but the right arm signal is easier to teach children: "Point which way you're going."

The study also determined that correct perception of arm signals was reinforced by the position of the bicyclist on the road. Finally, if a bicyclist looks back, drivers interpret it to mean that the cyclist is about to do something, but they don't yet know what.

The conclusion is that we should look back at drivers to get their attention, point in the direction of our turn, and move when safe to the correct road position for that turn.
The original research is reported in Drury, C.G., and Pietraszewski (1979) "The Motorist's Perception of the Bicyclist's Hand Signals," Ergonomics, 22.9, 1045-1057.

Right now Missouri law does not allow bicyclists to signal right turns by extending the right arm. The Missouri Bicycle Federation's 2005 legislative agenda include a provision to fix that problem.

Virginia allows the right arm signal for a right turn, so I use it. I think the drivers understand it better than the left arm up signal. It's more like a car's turn signal so it's more intuitive.

Extending the arm is the best way to signal. However, one should be aware that to be truly effective, this needs to be done on the approach to the turn and not during the turn itself. For one thing, you'll need both hands during the turn, and for another, you need time to gauge the reaction of drivers to the signal. The reactions of two drivers to a signal may well be different (even if they perceive it's meaning the same way), and it's important to realise what they are going to do.

Do you know...

The set-up on brake levers on US and Australian bikes is different because of hand signalling. In the US, the rear brake is on the right-hand side on the assumption that the rear brake is the preferred one to use while signalling with the left hand to come to a stop and for turning left across traffic. In Australia, the left lever is for the rear brake, on the assumption that the rear brake is the preferred one to use while signalling with the right hand to come to a stop and for turning right across traffic.

I found out about this when Americans started hiring my bikes. I quickly learned to inform them of the difference so they were not set up for some nasty surprises (ie, endos over the bars).

My Fuji was imported directly from the US and has the brakes set up for that market -- in other words, the opposite to the Australian practice. In works remarkably well because I use the front brake for most of my stopping power.

I think it's another case of product standards and legislation being led by advisers (I daren't say bike-riding advocates) who have no technical knowledge of bike dynamics.

As to the original intent of the thread, signalling (and early as Chris points out) adds to a cyclist's predictability on the road (and other places, too).

I allways try to signal even when there's no traffic about,mostly to make it automatic but also just in case I failed to see another vech.

I do this same thing for this very reason. When I started biking, I was a little lazy about using signals, but now that it is my main means of transportation, I am very vigilant about it. I also the "point" method to make absolutely sure that drivers know where I am going well ahead of where I am trying to turn. The only thing that I can't quite figure out how to do is how to signal when I am in a line of traffic at a stop light. I don't really want to sit there with my arm held out until the light turns green, but signaling at the last second when it does turn green seems a little to short of a time to have the arm out.
Kat

Make eye contact with the driver behind you, point to yourself, and then point the way you are intending to go. I also take the lane at signals, but move to the right as soon as possible after either crossing the intersection or making my turn. Be visible when I need to be, and as unobtrusive as possible when I can.

We were taught hand signals in driver's ed, to be used if your turn signals are obstructed or not working. I think the left hand, squared up is taught to drivers because obviously a right-hand signal is ineffective for a motorist.

However, even though it's legally accepted signalling, like most of the rest of the motor vehicle code, people actually behind the wheel don't know it. In my experience, you're lucky if 1 in 3 people know right-of-way rules that they should be using a dozen times a day; the odds of them knowing hand signals is remote indeed.

I realized this quickly when I started full-time commuting this year, and changed both what I do and what I was teaching my kids. I point the way I'm turning.

When I was a kid way back in the stone age the town I lived in Long Island at the time made all children go through a bike safety course given by the local PD. If you passed you where given a sticker to place on your bike. During the course the PD showed everyone how to use the then and as far as I know still only legal way to signal (right - left arm bent up at a 90 degree angle, left - left hand point straight out and stop - left hand pointed down).

When I went for my NYS drivers license some years later these same signals where in the drivers manual provided by the state. I sure the case is still the same today.

Today I am 55 and still use these same signals today. I go as far as using them during the few times I ride a sidewalk, just to show a driver what my intentions are (especially if I'm going to make a right turn onto the street) and in case there is another cyclist I may not have seen behind me.

The problem I see with pointing to the right to make a right is that drivers are so used to seeing other drivers stick their hands out the windows to do everything from flipping a person off to drying their hands that a driver may confuse a right handed point for something other than what it is. Then when he/she hits you screams you did not signal at all.

That's true enough. I've been honked at 3 or 4 times this summer, and I usually respond by waving at the people. I've noticed that in each case, the person assumes that I flipped them off. I can assure you that I didn't, but rude people always assume that everyone else is as rude as they are, I guess.

I usually extend my arm three times in the direction I'm going to turn. One time, though, I was signaling a right turn (and so I hadn't taken the lane and was off to the right side of the road) and my hand almost hit a mailbox.

Also when I signal I make a fist, except with only the index and middle fingers extended. I saw another cyclist do this once while I was driving and I thouhgt it made it very apparent that he was pointing, and not just stretching out his arm or something.

I notice that when I signal with my right hand and point a couple of times the drivers usually give me a nod to let me know that they understand. When I signal a right with my left hand they just look at me like I am giving them the Spock live long and prosper sign. I definitely like it a lot better when they nod and communicate, so I am sticking with using the right hand.

And as was mentioned, I signal even when I am doing my predawn ride of the empty streets around my neighborhood. Good habits are just as hard to break as bad ones.

I only signal a R turn when there is are car at the intersection yeilding the right of way to me. Then he doesnt have to wait for me to cross in front of him. I point with my R arm.

I (in right side driving land) always signal left turns and mostly signal right turns, both with left arm.

The funny thing is that on two occasions when making the bent left arm right signal I have had the middle finger given back to me. I think these drivers saw it as some sort of insult.

I do find that signaling left is far more important, signalling right in most circumstances is more often a courtesy.

Al

I signal both left and right turns. However, it seems to me, from the reaction of drivers, most of them don't know what I'm signaling when I signal for a right-hand turn. I guess new drivers don't learn hand signals anymore.

I use this method and pretty much all of the drivers around here can plainly see what my intentions are.

left arm bent upward.

Reason being that it's right in front of the driver, and therefore easier to see.

If I'm merging to a lane to my right...only hten will i use the right arm to signal.

It's just a matter of who has to know, or who should get preference in knowing.

I do the "pointing" method myself. However I kinda wave my arm up and down a little to provide some action. I figure they will see movement even more than just putting it out.

Peace

The logic of using left hand seems to prevail for most situations, but if you are a bit to the left of the right side of the lane and there's any question as to a car trying to sneak by on your right then get that right hand out and point emphatically. The preponderence of us are right handed and therefore most likely to control the steering function with a strong hand remaining on the bars. A head turn helps get attention as does a coasting cadence because both indicate some sort of forthcoming change. I ride a tandem so I usually leave the signaling to my stoker and she has much more time and visibility to work with than someone on a single.

I should get a monkey and train it to signal for me. I can just carry him on my back and I never have to take my hands off the bars!

In spite of living & riding in a state which does not recognize the extended right arm for a right turn, I signal a right turn with my right arm. Like Diggy 88, I also point with two fingers.

As an older roadie, I find performing the bent left arm for a right turn difficult from an aggressive road position. Sit right there as you read this, and make the left-arm, right turn signal. Now bend your forearm 45 degrees back from the angle of your upper body. Now many of you ladies out there may have no problem with this, but I think few of the gents can do it.

In my cycling classes, I teach & demonstrate the law and then show them right arm for right turn. I even done in from of Joe Law with no problems. Of course, I doubt they know the law.

Trust me, I'm a LCI.

This is why signalling should always be done in advance of the turn. If a driver is not going to understand my signal, I want to know this before I pull out, not half way around the corner. I find pointing to be the most decisive hand signal to give, but the problem is that there are people who simply will not comprehend any signal you give. Heck, even car indicators are unreliable around here -- given the number of people who use them with no intention of making the turn indicated.

Getting to work involves turning right in a right-only lane of a local highway (i.e. bikeable highway not country road). This lane ONLY goes to the place I work and nowhere else. Anyhow, to make this turn at speed I need to be out in the middle of the lane despite the generous shoulder. I tend to move out into the lane long before the turn and signal numerous times. I also look back a lot. Despite this, someone once passed me on the right just as I was about to make the turn. Fortunately, he was turning too or I would have been a pancake. At the security gate the guy apologized quite sincerely so I let him go without any street justice.

Anyhow, I signal with the right arm in that spot every time. I used to always signal with the bent arm thing until enough people told me how ineffective it is on the bike. I still do the bent arm thing somtimes out of habit.

Right arm for right turns. They apparently don't teach hand signals down here anymore and it's the best way I've found to make myself understood.

That's why we call them "Idiot Lights" mate!