Couple of items additional:
water (couple of small bottles would be fine), candy (chocolate preferred), some trail mix (peanuts, crackers, and such), gloves (leather, wool), wool hat, wool socks, wool scarf, old jacket, newspaper, card board, matches, road flares, flashlight, hand mirror, fix-a-flat, hand tools (SAE/Metric), cross-bar lug wrench, tire chains, roll of tp,
Strap shall only have loop ends, no hooks. Use clevis/d-rings to attach or loop itself through.
Water will tend to freeze, but rarely will the plastic crack and leak. Soda will make you more thirsty. Candy for energy as well as filling. Same for the trail mix. Wool clothing when wet will still hold body heat. Newspaper for easy starting a fire. Card board to block the air across the radiator, this keeps the coolant a little hotter. Mirror to flash sunlight if/when necessary. One time use fix-a-flat is good to help, but may cause damage to the tire/wheel. So careful consider use on it. Other tools are self explanatory. Cross-bar is a lot easier to use than the stock lug wrench.
Other things like letting someone know where you are going, carrying a cell phone (old phones can be used for emergencies only |removethispart|@ no cost. Dial 911 (US) for help.) Roll of tp is self explanatory.