Next to spaghetti, tacos are the worst food try and eat while you're driving a car. They're messy when you're just sitting at a table; they're a straight up disaster when you're trying to eat one in a moving vehicle.
Hard shell tacos in particular are definitely not ideal for on-the-go consumption. The first bite somehow destroys the structural integrity of the entire shell and suddenly you're left with a lap full of broken tortilla bits and broken dreams. And lots of taco filling.