I've looked into it, and the ordinances don't require landlords to clear their parking lots, just the public sidewalks.
Update: Since I posted my rant, I have heard through the grapevine that the man my landlord had contracted with to clear our parking lot this winter couldn't find enough drivers for his plows and so had to cancel his contracts, among them ours. It never occurred to me that the landlord himself was having a problem, I was just thinking about my own problem. Oops! Well, I really hope that next winter turns out better. In the meantime I'm watching the weather like a hawk and trying to salt pre-emptively whenever possible. This morning I did that, and I also salted around my neighbor's truck (he was kind enough to clear off my car after the last storm).