Abstract
Recently, propositions for new European Commission Directives have been developed in Brussels. By means of them, next Directives will be adapted to technological progress:
74/408/CEE (strength of the seats and their anchorages), 76/115/CEE (safety belts anchorages) and 77/541/CEE (safety belts). The objective of the adaptation is to extend their scope to collective transport vehicles (M2 and M3 categories).
At present, Spanish buses and coaches makers can apply in an optional manner to their vehicles the ECE 80 Geneva Regulation, related to strength of the seats and their anchorages. The aim of that regulation is to assess whether or not the seat occupant is correctly retained, in the case of a frontal impact of the vehicle, by the seat in front of him.
With safety belts legally binding the situation changes completely, because the own seat retains the occupant, and efforts over the seat come from the occupant. But there may be other possibilities too. The most unfavourable one occurs when the seat occupant wears the safety belt and the back seat occupant doesnt wear it. In that case the seat receives the efforts from the two passengers.
ECE 80 Regulation prescriptions have been the ones included in Directive 74/408/CEE about strength of the seats and their anchorages. Anyway, article 3 in 96/37/CE specifies a period for the revision of some aspects in the directive. From them, we can show up the equivalence between static and dynamic tests, and seats strength in the case of combined loading.
In this paper, raised questions referred to M3 category vehicles are studied. The followed methodology includes next points: analysis of the prescriptions in the regulations, analysis of current solutions in Spanish market, mathematical modelling and simulation of seats and passengers, static and dynamic tests over seats and anchorages according to regulations, dynamic test of an unrestrained passenger impacting to the back of a seat occupied by a passenger wearing the safety belt, several use conditions simulation, and conclusions including based on different tests and simulations proposals of modification into the current regulation.