Car Prepping

What can I store in my car to prepare for traffic related emergencies?

Context: I live in a blue area that's urban to suburban with heavy traffic on a normal day. I commute most days on major roads to a city. Taking public transportation is not an option for me.

I am concerned that I will be stuck on a highway for a significant period. The issues could be a natural disaster, civil unrest disruption or even just a terrible accident. Many years ago, there was a massive accident that forced not only the highway but all the side streets to a literal standstill. It took me 3 to 4 hours to go 12 miles.

I'm working on prepping my car. To date I've added:

-Stable snacks - emergency blanket - emergency reflector light - jumper cables - air compressor for tires - seat belt cutter/ window smash tool - emergency whistle - umbrella (Tuesday prep!) - road map (edit)

What else do you include in car prep? How are you storing water? Our temperatures can be 0 to 110? I'm not trying to live in my car or anything, just spend an extended stressful period in it.