I have roughly 8 miles of my 16 mile commute in heavy traffic. I still breath a sigh of relief once I hit the MUP. But when I ride in traffic, I always wear my bright yellow vest and try to make eye contact with drivers. I also, learned the hard way NOT to let drivers " be good Samaritans and stop, to let me pass".
Car drivers just do not watch traffic from a cyclists point of view. I always give them the right of way. I feel better when the cars are out of my way so to speak.
I always just make sure to constantly be aware of my surroundings and actually found that drivers are far nicer to me as a cyclist than I thought they would be.
Also, it helps to do practice runs of your planned route on a non- work day. I found I needed to change one section that was too crazy for my liking, and you can time yourself too
2012 Trek Lexa SL
2012 Giant TCX2
2015 Trek Remedy 7
2016 Trek Lexa C
2016 Specialized Hellga-Fat Bike