I'm not sure why the big concern with buying packaged water for your vehicle. For a longer term emergency situation - OK but AquaBlox is awfully expensive to go that route.

I use regular bottled water bought by the 35-40 500 ml bottles in slats. The other day I paid ~$4.50 for 40 bottles. I can store 7 litres in my car at any given time and I do all year round. I consume then recycle the bottles. They hardly ever freeze - even on the cold prairies of Canada since I garage the car in an semi-heated 0*C garage every night. The vehicle has to get to -15*C for an extended period before I have ice forming. That may seem to deny the laws of physics and chemistry but really it takes a while to chill the car off and secondly water in a closed container doesn't freeze at Zero. However, if you take the same bottle of water that has been in freezing temperatures and give it a good shake, ice will form. Or if you release the cap and change the air pressure, the water will instantly create some ice. Even when the bottle is frozen solid, I have never had a bottle burst yet. If it is frozen I simply swap it out for a thawed one.

Summer time is no big deal either - even when the car is 40*C or higher inside, the only thing the water does is get warm and the plastic gets a bit more malleable.

I drink water quite often while driving (especially on long trips) and I don't care if it teeth chattering cold or coffee hot. I have a constant turnover of the water in the car between myself and my passengers.