Mandalay Parr wrote:
I’m an engineer and not aware of any such formula.
I'm a traffic engineer and yes we have software (autoturn) to do this but not convenient for a layperson to obtain. You could go to a local engineering firm but it likely doesn't make financial sense unless it's a buddy who will run it for you.
If you google "turning templates", you can pull up pre-made ones for various design vehicles that will give you a good idea of what to consider but we don't normally design for RV's (to many variations).
The idea to find an empty parking lot and then simulate the turn while marking it out is a good option. Make sure to add a little extra width as you won't hit the curve exactly down to the nearest inch every time. The outside sweep of the rear overhang doesn't need to be paved, just clear of trees and other obstructions.
One complication to consider: Is it a simple single turn? Or do you have to turn left off the road and then almost immediately turn right? If, yes, when you go out to the parking lot, make sure to simulate the entrance and exit maneuvers.
