"if I was on a duel carriageway I would always hold primary in the inside lane to encourage motorists to overtake in the outside lane, and to stop people squeezing past in the inside lane (while undertaking someone in the outside lane)." i ride in a city everyday and i would never do this. i rarely ride on dual carriageways but if i do its outside of rush hours and its a meter from the kerb or so.
listening is they key for me. and looking back. for instance, if there is a lot of traffic sound coming from the rear and it sounds say up to 200 meters off ill look back quick and if both lanes are being used by vehicles ill move in closer to the kerb. if the sounds are very close behind because i haven't paid attention for ten or 20 secs ill just move into the kerb. drivers come by close, there is space for everyone (slim but safe imo) and as well as my own safety i dont want to cause vehicles to crash through dodging me in primary if they haven't see me you know. avoiding shocking inexperienced or inattentive drivers is my aim.
on a bike, its quite easy, if your a driver to understand what a vehicle is doing behind, with respect to them slowing, descending the gears, braking sounds sometimes, engine changes in tone, to know if a vehicle is slowing behind me readying to move into the outside lane once the faster car has passed themselves and me.
I just dont trust some drivers enough to be ready to move into the outside lane once they've seen me, if im riding primary. their previous collective driving doesn't warrant trust, they've got music blaring, chatting to friends, texting, kids in back, rushing to work and on and on.
sorry for criticizing im just reading through some threads.
edit spelling.