Microsoft has developed a drönarsimulator which is intended to test the use of drones and, by extension, other vehicles, in a photorealistic environment.
the Idea is that developers, for example, to test the new software for their drones in the simulator before testing them in a real environment.
In this way you can early found bugs and other things in the new code, and may avoid to destroy the real use of drones in the event that the new software would contain errors.
One of the developers behind the AirSim says in an interview with The Verge:
"You can do a lot of experiments, and even if those experiments fail they have very little cost in real life.
In the real world it's extremely hard to explore all possible things, however in simulation we have the luxury of trying out many different things."