Thanks for the kind words, look like an interesting project.Have you tried turning on Align Y to Surface
from the Segment's properties?
It will rotate the object around the X Axis to align to the underlying surface and may help in this case. With bend on the results are pretty good but with bend off there is some intersection as it reaches the top because the X angle is calculated from the point at the back of the vehicle, not an average over the full length.
I hope that helps, please find the sample file attached.