> A field is sort of a best case scenario for autonomous vehicles

There is no “autonomous tractor law”, the headline is misleading. There is a farm safety law that has been in place since long before any autonomous production farm equipment existed which prohibits self-propelled equipment without the operator seat occupied at all times while in operation. It was not unheard of for people to get on and off low-speed self-propelled (that was not self-driving) farm equipment while in operation, in an attempt at efficiency/multitasking, with attendant safety risks. That’s what the law was directed at.