If you want safest motorhome,build one from old schoolie bus
http://www.ed.gov.nl.ca/edu/k12/busing/p_safest.htmlSchool buses are designed to protect passengers on board from impact. To accomplish this, just about every feature of this design was specifically chosen to reduce the effects of a collision. School buses are required to have increased body strength by the provision of horizontal full length impact rails located at the shoulder, cushion, floor levels and lower shirt levels. In addition to the sheer size of the bus, the floors are raised protecting the students by having them sit above the impact zone where an automobile would typically hit a school bus. The bus is further protected from side impacts with the design of the windows, shaped small enough to prevent passengers from being ejected from the vehicle.
The school bus is specifically designed to reduce the shock of impact with a moveable structure. In order to absorb the energy of a collision the bus is structured to be able to slide up to 12 inches along the chassis frame.
There are also rollover precautions put into the school bus design that reduce the risk of serious injury caused if the bus were to roll. The interior of the bus is a smooth rounded shell, free from sharp edges. The goal of this design is to ensure that the energy from an impact is absorbed by the entire body and not just certain areas. There are also various emergency exits placed on both sides of the bus, the back, and an escape hatch on the roof.
Heres a Fine example
https://youtu.be/o7X2nOtwdUM