No one has disagreed yet so I disagree. I think OP should protect his ears, maximize the enjoyment he gets out of all that time spent biking, and continue using his own judgement about how loud traffic noises around him need to be to keep him safe enough. Getting tinnitus (which is hellish) is more likely than earbuds being a deciding factor in whether he gets injured in a bike accident. I don't see why the decibel level a cyclist is exposed to should be greater than the decibel level a motorist is exposed to.