I need to get three sheets of 1/2" plywood home from Home Depot. If I ratchet strap them to the top of my mazda 5 and take it slow (like 30mph tops) will that work?

I really do not want to have to get a truck. it's like 2 miles away from my house

@csalzman I would also attach front and back. We would use paracord ties to toe hooks and frames at the front and back of the car when we had kayaks to counteract any updraft.