I'm also a defensive driver and have outstanding peripheral vision if that is not impaired by a blind spot. Unfortunately blind spots have appeared in more and more vehicles over the years mainly I believe due to the fact that adding a backup camera is cheaper than designing out a blind spot. This does nothing to solve when a vehicle in the drivers passing lane which means the driver will see someone approaching in their rear view mirror then pick them up approaching in the drivers side view mirror only to lose any view of them from the time they begin to pass the drivers side rear to the time they just pass the rear portion of the drivers side front door, this is what I call the dead zone and what causes a good driver to change lanes, not because they were not paying attention but due to that dreaded dead zone. The only solution is a blind spot mirror, I have used one on all of my vehicles since 1985 and the CT has one as well. The passenger side mirror has enough what I call fisheye view to it I get a miniature view of what's happening, at least enough to not blindly get into that lane. A long term solution would be all drivers side mirrors come with a split view mirror like some trucks and SUV's have, it makes one section the dead zone mirror and some are adjustable.