In the UK we have small 'bricks' (around 150ml-5oz) of fruit juices and I suspect you do too.

I like the original Ribena and these have enough sugar in them to depress the freezing point significantly. In the case of Ribena to about -5ºC 20ºF. In the car, in a pack, they stay liquid after an overnight -20ºC -4ºF but will freeze if exposed longer. When they freeze they just expand a little and repeated freeze/thaw cycles do not burst them nor affect the taste.

They also, of course, have an energy content over water which would be useful in cold conditions.