Abstract
Regulation 66 was an improvement in the passive safety of coaches under rollover accidents, but this has carried a weight increase of their structures.
Also, the general safety systems in the vehicle (antilock brakes, improvements in fire behaviour, seat and anchorage strengths, seat belts,...) and confort elements (like double glass windows, video and tv, more comfortable seats,...) have led to a heavier coaches.
On the other hand, changes in weight and measurement regulations have raised the length of the vehicles keeping the same structure. This situation requires greater energy absorbing capability of these kind of vehicles.
The introduction of mandatory seat belts for passengers contribute to reduce the injuries in rollover cases, but may lead to higher requirements on the vehicle structure, as it is shown in the works presented by INSIA. In this work it can be evaluated this effect by the increase in the deformations an the energy to absorb.
So, it is necessary to study different alternatives to increase the structure energy absortion capacity to keep the safety levels in the current status.