On: AirSim: open-source simulator for autonomous vehic...

[draugadrotten]

If using Unreal, the assetto corsa competizione video game is pretty good for simulations and it offers a commercial license. https://www.assettocorsa.net/assetto-corsa-pro/

As does rFactor2 but it may not be so easy to use with unreal.

http://www.vesaro.com/store/pc/viewPrd.asp?idproduct=130