I do the #5 #9 test. If there’s ice all over the car windows, I get one of the Hybrids out, wear all the thermal kit, and ride on the roads that have obviously been treated, it might involve a slightly longer or more convoluted route, and *shock horror* I might actually ride on a road with more traffic on it, than an iced up back road, but traffic beats ice, in a game of ‘cycling rock scissors paper’. I’ve been out in -6 ( at its worst so far this year) and I’m not dead.