In the new version 4.14 the vehicle physics are works, and the old bugs keep there (the vehicles that can climb walls).
If you use the vehicle sample template and place the vehicle wheels between the road meshes and move the car then the car is launched to the space (sometimes do backrolls others go to the space doing infinite backrolls )
Plus Substepping freezes the vehicles even if the vehicle is custom made with line traces, then launch the vehicle to 10000Km from the World Origin. I can’t even use a box in this engine version right now…
https://dl.dropboxusercontent.com/u/28070491/GIFLOL.gif