Aside from everything else everyone says about high viz stuff..
I plan my route around the roads and traffic. I spend as much time as possible in places that are less likely to get me run over. These include roads that are super wide, have minimal traffic, going behind stores and using parking lots of stores that aren't open yet during the morning commute time.
I have the option of using main roads, but there is no reason to put myself in a more dangerous situation that I need to be when safer alternatives are available.
Now, my commute is short. So I have a lot more flexibility to add 30% - 50% in distance to ride on safer roads. If you are riding 20 miles, adding 6 - 10 more miles can make the trip take longer than you have. For me, 50% more distance is adding 10 more minutes. But if you have a short commute and can take the meandering route on lower used, wider roads, and use parking lots and access roads with limited or no traffic....you reduce the chance for a collision dramatically.