All I know is that I was told at least a dozen times before I was hired "If you aren't going to be there everyday for your first 30 days, we don't have a job for you." I don't know if your hiring staff was as clear with you. Take your own chances but I would make sure I was there for the shift I agreed to be there.
All I know is I had a no-call, no-show in my first 30 days due to either not setting an alarm or sleeping right through it. Came in the next day business as usual.
A year and a half later, I'm still on the preload.
So yeah. It's kind of 50/50 for you, Ant, but I'm willing to bet that, if the roads are truly as bad as you say they are, your job'll be fine. That's by no means a guarantee, though, so don't get angry with me if I turn out to be wrong.
[EDIT: If you're not going in, though, make sure to inform your management team. I got lucky with my situation, there's no denying that.]