I should be more clear, I wouldn't leave stuff in my car and go about my day, nor would I likely be on highways (I'd just lay low someplace I think is safe) during an event like this (Blizzard, hurricane, what have you). I'm just saying, I saw cars up to their roof in water on the highway, while the other lane was almost bone dry with a jersey barrier in between. If I were to be stuck in traffic with rising water, I'd want to be able to grab a bag, jump the median and hoof it to relative safety.

I do keep things like a knife, flashlight, fire starting equipment, etc, on my, at all times, but having a quickly accessible bag-o-stuff to back that up wouldn't hurt.

In fact if one read's DR disaster prep car kit he suggest keeping it all in a backpack...I'm just a bad listener