Beginning this fall, green 14-ton tractors that can plow day or night with no one sitting in the cab, or even watching nearby, will come off the John Deere factory assembly line in Waterloo, Iowa, harkening the age of autonomous farming.

The development follows more than a decade-long effort by the world’s largest farm equipment manufacturer, and marks a milestone for automation advocates, who for years have been explaining why driverless cars aren’t quite ready for prime time.

“I’m glad to see they’re coming out and will stimulate the other technologies,” said Raj Rajkumar, a professor at Carnegie Mellon University and an expert in autonomous cars…

But, Rajkumar notes, tractors have it easier because they don’t need to contend with other vehicles, pedestrians or the complexities of an urban scene. Tractors can make use of consistent GPS data, unlike cars that can lose contact traveling through tunnels or amid tall buildings.