This is my second winter road cycling, and the majority of my winter riding is done at night. Last year I had reflective tape all over my helmet, a MagicShine 900 on my handlebars, reflectors on the back of my shoes, and one or two red blinkies underneath my seat. People generally gave me tons of room when passing, and for a while I felt much safer riding at night than during the day.
For this winter I added to all of that a second rear blinky by my left rear dropout while still keeping one under my seat, and added a ton of reflective fabric to my jacket to the point where it probably looks like I'm wearing one of those construction worker safety vests. My goal was to make myself more visible to motorists and make my arms more visible for hand signals.
However I've found over the last two months that I've been riding with this setup cars are passing me significantly closer (although not getting buzzed), and trying to take the lane to prevent unsafe passes has been far less effective than the rest of the year. I feel that I've removed all uncertainty of my position on the road, causing drivers to pass me more confidently (and more closely!).