Reason #129 why pedestrians and bicyclists should not have combined lanes: the pedestrians make the roads uneven. It is impossible to ride straight on a path trampled in snow by pedestrians. It is much easier to ride in 15 cm (or more) of untouched snow.
Even though bicycling in an unmaintained infrastructure is hard, I'm not even considering to switching to commuting by bus or car. Co-workers often seem to think that bicycling in winter is extreme. It may be extreme in the sense that riding in the snow is heavy and you have to either strain yourself or go really slow, but at least commuting by bicycle is reliable. The duration of my commute may be two (or even three) times longer in the winter than it is in the summer, but it is highly probable that I get to the destination in the estimated timeframe.
In my opinion, commuting by train or bus in the winter is extreme in the sense that their reliability has not proven to be that good. In fact, the reliability of the railroad system in wintertime has, in recent years, proven to be a joke. Buses may be more reliable than trains in the sense that they usually get to the destination, if you actually manage to get on the bus, but in my experience their schedules seem to be relatively unreliable. It is not that rare to have to wait on the bus stop for a shift that never comes.
And, of course, commuting by your own personal automobile is extreme in the sense that it is, at least in my case, slow, stressful and stupid. Also, it is unreliable, because I can never rely on finding a parking space near the workplace, and the duration of the commute depends on the heaviness of traffic. At times of heavy traffic the cars crawl slowly in queues. This has never happened on bike lanes, as far as I know.
BTW, bicycling in the snow is good exercise. Last winter my thigh muscles became larger in diameter approximately 15%. If this trend continues, next spring I'll have to don silly looking pants:
Speaking of silly garments, winter seems to have surprised, despite people, also my shoe protectors, that until now have functioned exceptionally well. This morning they apparently got scared of the snow, curled upwards and refused to cover my toes. So perhaps, come spring, this is what I'll look like:
Actually, this costume seems well suited for bicycling. The shoe protectors seem large enough to cover size 45 cycling shoes. The pants are comfortable and spacious enough to accommodate my enormous thigh musculature. The feathered hat can be worn as a helmet cover.
But then again, cyclists often wear clothes that are too soft and not sufficiently awe-inspiring to ensure their safety. I mean, car drivers avoid collisions with other cars because they know that their precious cars would be badly damaged if they hit another car. If they hit a bicyclist, perhaps the dust might be wiped off the car, but the car would most likely remain intact. But what if bicyclists started dressing up like Dimmu Borgir? No Mercedes Benz driver wants to have Shagrath sliding over their bonnet: