Eating is fine when it meets three criteria.
- Low traffic density, like a highway with very light traffic. Residential streets are never acceptable places to eat while driving.
- The food should be a moderate temp and manageable with one hand, and unlikely to make a mess. Like fries, a wrap, or some carrots and other small snacks less that aren't messy.
- You do not care if something l falls on you. Literally don't care enough to do anything until you reach your destination. If you can't help but try and catch or look at dropped food then don't.

Basically eating in the car is acceptable on long drives with food you can drop randomly but only if traffic is light.