It's the fear factor that keeps you alive. Knowing that you can easily get bumped off by cars let's you stay on your Q's: keeping alert to your 360 surroundings at all time, paying attention to what can happen every moment of the ride esecially for park cars with someone in them, driveways that have a blind spot, a car behind you passing by, and looking ahead for whatever is taking place by the time you get there, and being prepare for a unleashed dog: by having a mace spray available, or water bottle at hand and open ready to wet it if you have too; practice this to see how it works. A friend of mine rides with a left rear mirror when he rides, but I think you can see behind you just by turning your head back quickly for a fast glance. My theory is look for what can happen and be ready to do something before it happens to you.