Best for Driving:
McDonald's Cheeseburger: The ideal burger for driving. Compact, delicious, and drip-free.
Starbucks Bacon & Gouda Sandwich: Streamlined and tasty. Like eating a delicious wallet.
Taco Bell Potato Taco: One of the only things at Taco Bell that is unlikely to ruin your shirt.
Chick-Fil-A Chicken Sandwich: A classic for drivers and passengers alike. Tidy and delicious.
Wendy's Jr. Cheeseburger Deluxe: The only lettuce, tomato, and mayo burger I guarantee will not drip on you. (This is not a guarantee! I don't know you.)
KFC Popcorn Nuggets: Tricky to dip while driving, but bare naked they are still decent.
Popeye's Chicken Sandwich: Comes in a neat foil pouch that can be peeled back like a banana to contain possible spillage. It can also be tossed like the banana peels in Mario Kart. (That doesn't really work, and don't litter.)
Worst for Driving:
McDonald's Big Breakfast with Pancakes: Only conceivable way to eat this is to roll the pancakes into tubes and gnaw on them.
Starbucks Spinach & Egg White Wrap: Super drippy. The single wettest, leakiest breakfast item I've ever encountered.
Subway: Everything from Subway except the wraps and who gets wraps at Subway?
Taco Bell Crunchy Taco Supreme: Delicious but your car will be filled with shredded lettuce, cheese, and tomato bits and so will your clothing and facial hair (if facial hair is your thing).
Burger King Big King: BK's Big Mac rip-off hemorrhages sauce like it's been fatally wounded.
KFC Cole Slaw: Even if you forgot the fork and pour it into your mouth you will be soaked with slaw juice.
Panda Express: Everything from Panda Express except the cream cheese rangoon and spring rolls
Wendy's Baked Potato: The only possible way to eat this while driving is to pick it up and chew on it like an apple but it's also 400 degrees so you're going to need oven mitts and those are definitely going to affect the steering wheel.