The posts above are right on. You and only you are responsible for the safe operation of your vehicle. The company might send you out, but you must use your skills and knowledge to operate your vehicle without getting into trouble. And in some cases, that means not getting off the main drag.
Ice, true ice, is almost impossible to drive on. A few weeks ago, we came through Atlanta on Monday after that storm they had. We were on the interstate. Several 18 wheelers had tried to make it through a small dip and rise in the road, only to slide back down, and blocked the road. We got a good show when the tractor beside of us tried to move on level ground, and all he could do was slide and spin. You are better off not trying to deal with ice on its own. If it has a covering of snow, or has a rough texture, it is somewhat better. But still dangerous.
So while there are not laws on the subject, you need to focus, and avoid places where you might be able to enter, but not be able to leave. And as Cach posted, hills and mountain areas pose their own problems.
And the biggest threat is not so much the ice, as it is the other drivers on the ice. They are actually the biggest problem you will encounter. So drive defensively.
Hope this helps some.
d