Pot holes are not deliberate road conditions but happen. Yet they still pay Refusing to salt, brine or close a road to save money is a deliberate mismanagement.
So you don't understand. I'll lay it out for you.
Drivers are 100% responsible for the safe operation of their vehicles. A pothole is actionable (damages are generally limited to specific vehicle damage) because they don't happen all at once and are just outside the envelope of a driver's obligation to operated their vehicle in a safe manner.
Ice, on the other hand, represents a condition wherein the driver should have been aware of the conditions and, from an abundance of caution, chosen not to operate the vehicle because those conditions are inherently unsafe.
In short, potholes and ice are not the same thing. If you go out and peruse the FAQs on the web sites of the large ambulance chasing law firms, they will tell you quite explicitly that you do not stand a good chance of winning any suit brought about with regard to icy driving conditions. You choose to drive in an ice storm, the outcome is your responsibility, period.
Also, just noting for the record that you have been unable to cite a single case wherein a vehicle operator was successful in obtaining damages pursuant to ice and loss of control.
Now, if you go out and subsequently get hit by a city-owned vehicle, that's a different story.