Out here in California we can split lanes. Lane sharing is a way of riding in most of the world, a recent study at Cal Berkeley found that the perceived dangers non riders associate with the practice are not nearly as severe as cagers believe. And one of the great benefit? Our incidence of rear-enders is nearly half of our national statistics. Motorcycles were never intended to be standing still, sitting at iddle.
If you haven't already, read the 'Hurt Report'. It helps identify the biggest threats we face when riding. Rear enders, while real, are not in the top ten.