Do you need to be a diehard about this? Obviously, in an ideal world, we wouldn't NEED to eat in the car, ever. In fact, one particular parent I know absolutely refuses to allow her kids to participate in any activity that would necessitate even a car SNACK. They pulled their kids out of a sport because they wanted to take a stand.
Or can you be more situational? It seems like most parents - offline at least - get that sometimes, it's a necessary evil. And if so, some tips can help.
Avoid certain foods. There is some truth to the choking fear. Hot dogs, grapes, anything small and round and hard probably shouldn't be eaten by a young kid when the adult present has their focus on the road. But even a toddler can usually handle Cheerios or goldfish.And unless you really like stain removal, probably also a good idea to ban milk products, chocolate, and sticky or staining food. I personally banned anything RED.
Be committed to clean up. Whether it's adults or kids, if you allow food in your car, you should vacuum your car at least weekly, and give all surfaces a wipe with either a damp cloth or interior cleaner.
Address spills immediately. This is a big one with us. My kids are always in a panic when something happens, but I tell them, every time, I would rather KNOW right away and clean it up, then find it later when it was a big problem. All the passengers in the car who are eating need to agree!