For what it's worth I cannot ride on road without a mirror - on long rides I listen to music. I ride rural highways where there is little traffic. But, seeing vehicles coming I can tell if they have seen me and are moving over. Only one time have I noticed a van coming and did not move over. Luckily it was not going real fast - I bailed off into the gravel and the van stopped and driver was pleading his apology that he did not see me and he was looking off into field at deer... For that instance alone I owe my life to a $12 mirror on my shades. After breaking many of the "Third Eye" brand I use electric tape to hold them in place. Works pretty good -