[phicoh]

I don't know where you live that you have that much space. My personal rule is don't swerve. If you don't have time to signal that you are going to move, or look to make sure other traffic is not in the way, then either brake hard or continue straight (with the obvious exception if not swerving causes you to hit another person).

There are just too many roads where you can't swerve without causing a head on collision. If you make it a reflex to swerve, then you will also do it when there is no space for other traffic to avoid you.