Certainly a company can ever fully pay for such an incident. Thanks to the court system, we have placed a price tag on the value of human life. People will sue, companies will settle, and life will go on. It's a horrible tragedy to be sure, but at some point you must be practical about it.
When a company is fully responsible for a persons death I do not believe they can ever fully pay for such an incident. I believe they are capable of throwing money at the situation and apologizing, but the cold reality is that they will continue to operate and profit, despite their failures.
The company can pay as much as they want, but the public will always remember this act of not paying attention by one of the companies drivers. Since it was a pregnant woman who was killed, the public outcry will be even worse than it normally would, since it hits them emotionally.
No one can pay the family of this woman enough to make up for the loss of her life and the potential loss of another one. However, that does not mean reparations should not be made if the company that owned the tractor was at fault because the family deserves something and the company needs to feel some loss so it will be more careful later.
A tragic accident due to weather conditions resulted in a death. Assuming the company who owns and operates the tractor is found to be at fault, the woman's survivors will always feel the loss. No amount of monetary compensation will ever make up for that. That is not to say that the family shouldn't be compensated if the company is at fault.