When the wife and I travel on a trip, especially in the winter, I make sure I've got extra fuel, water, food and snacks, canned alcohol heat, a plastic bucket, plastic garbage bags to fit the bucket and toilet paper.
We were traveling up from Florida about to go through Atlanta one time. Being me, I said to the wife...we're going pull off, top off our tank and take a pee break before hitting Atlanta. We hadn't been back on the road for more than three miles when we got stuck in bumper to bumper traffic in Atlanta for 6 hours. No accident, no nothing... just gridlocked traffic. There is something to be said for trying to plan ahead.