For short term, things like granola bars (without chocolate), jerky, and such are OK.
For longer term, I've found very little that does well at the mercy of the temperature extremes usually experienced within vehicles. Even freeze dried foods and such have dramatically lowered shelf life under such extreme heating and freezing.
The best thing I've found for relatively long term storage in vehicles is "lifeboat rations" or "S.O.S. rations". Here's an example of something I've gone with, albeit one with some extras for water and more accessible snack like portions: S.O.S. Rations Survival Emergency 3600 Calorie Food Bar + Pouch Emergency Purified Drinking Water + Assorted Millenium Energy bars w/Tips Guide by Jeff Brown I split that up into 3 reasonable sized sets for each of our vehicles. It's not enough for long term, but should be very helpful for something like an unexpected overnight emergency during a blizzard.