Originally Posted by genec
John, whether it is legal or not, I certainly don't find it to be a very safe practice, and I am somewhat surprised you would condone it in any way. That rather confused state of the motorists ("as they sort themselves out... ") can easily lead to a situational decision error... where a motorist responds to the other motorists, and blanks on a cyclist upon whom they may be closing.
Just doesn't seem like a good place to be.
I too used to do this, and now I just take a very well defined position in one lane or the other.
On a downhill portion of my commute home, I ride through a freeway interchange with a new lane joining to my right. The traffic coming up beside me to my right normally travels about 45 without a cyclist present, and the traffic in my lane usually travels about 50-55 without a cyclist present. With me there, they slow considerably. And with gravity, I'm doing about 30-35. In this situation, I find the best approach to the union is to ride near the right lane line, looking back to the right for a gap in traffic in the new lane before merging across it.
I've taken the right half of my lane (right tire track) when approaching this union, and that works too, but I felt concerned that the drivers behind me might try to overtake on my right by moving into the new lane, and so I prefer to entice them into overtaking on my left by riding closer to the line.