I did it last year. Coldest temperature was -18 degree C
the temperature is a problem because at that point if u breath too much it can damage your lungs..so slow driving is adviced. but not so much because of ice. just get some spike tires and its saver to go by bike then by foot because they really dig into the ice. should be legal in most countries since it is in germany. snow on the other hand really sucks.
should be legal in most countries since it is in germany.
In the USA it would come down to what state you live in. In many states bicycles must follow all vehicle laws, and I cannot remember a state where cars/trucks/etc. can use spikes in the winter. However, many states are finally making exemptions just for bicyclists. My state only legalized spikes a couple years ago.
However, that doesn't really stop cyclists from using them. In addition there really isn't any enforcement since officers have better things to do than minute inspections of bike treads.