I mostly ride through residential arterial roads and on larger roads (Congress in Austin) with substantially wide bike lanes. Together with that and a glasses mounted mirror, I feel pretty safe on my daily commute. I also take it pretty slow, always signal, and otherwise adhere to traffic laws (don't blow lights, stop fully at stop signs, etc).

All in all, commuting doesn't make me contemplate my mortality any more than usual. I've gotten to the point where I bought a longtail cargo bike and am confident enough to drop my three kiddos off at school/pre-school on my morning commute.