This is truely a great topic.... Like somebody else just said, I have been out of the loop for a bit and just got into this discussion.
In a past life as a fed (NHTSA) I also sat on this committee, or one like it... and I will use my fed experience to provide some info on this topic, I have been thinking about it for a few years. In the past few years NHTSA has done lots of studies on how to reach people with traffic safety messages. Their whole seatbelt media message (Click-it or Ticket) was designed to reach a certain age group, the group that statistics said were the least likely to use a seat belt. By identifying the group they could identify general characteristics of that group and then tailor a message and media outlets to them.
When we are talking about the car driving public as a whole there is no one media outlet or type of message that will stick with all of them, or grab their attention. This makes it difficult to get a message out to "everybody."
The same is true for the motorcycle community. You are not going to reach a harley rider the same way you are going to reach a sports bike rider, the same way you are going to reach a cruiser or a dual sport rider. And the messages themselves to these riders needs to be a little different to address them... that is what they will listen to.
...oh and I have to say that I firmly believe it is more important to educate the riding community than it is the motoring public. From my perspective, we shoot ourselves in the foot more times than we help ourselves... the majority of the riders I see are not the nicest people to people in cars.
I guess what I am saying, my experience is that there is no one size fits all for either the riding community or the driving community. So any single message will have a limited effect. But.... there was one message medium I liked alot.... the freeway message boards. You have a captive audience and it gets to most all of the people we want to get a message out to....
The two problems... limited space, and distraction. Everytime there is a message on one of those boards, traffic stacks up.
And.... the last time it was used it was a message to car drivers.... put out a message to motorcycle riders... I think this is important for two reasons... shows the car drivers that it is recognized that motorcycles can be part of the problem, and it reaches most types of riders.... How about a message like, "Riders, slow down between cars."
And last but not least, Data Dan and I have been talking about this very topic for a few months now... As always Dan is on the money and on time with what he does... I am dropping the ball on what I need to do.... My position.... when done correctly, lane sharing represents a distinct safety advantage to motorcycles... but like I said before... we shoot ourselves in the foot more times than we help ourselves..... and like most people say... it is not me... it is that other rider... that stupid (fill in the blank) motorcycle rider.