A vehicle comprising: a housing ; a vehicle seat disposed in the housing; and at least one radial slit disc energy attenuation assembly including an upper end coupled to the vehicle seat and a lower end coupled the housing; characterised by the at least one radial slit disc energy attenuation assembly including a slit disc stack having a plurality of deflectable discs configured to deflect in response to realizing a force applied by the vehicle seat; wherein the slit disc stack extends along a central axis, A, from a lower stack end to an upper stack end to define a stack height, wherein the plurality of deflectable discs comprise: a plurality of slit discs and a plurality of spacer discs , the plurality of slit discs, and the plurality of spacer discs vertically stacked in an alternating arrangement with respect to one another; and wherein the at least one radial slit disc energy attenuation assembly further includes a plunger extending from an upper end to a lower end, the lower end positioned proximate to the upper stack end and configured to penetrate the slit disc stack in response to receiving the collapsing force applied by the vehicle seat, wherein in response to penetrating the slit disc stack, energy is transferred to at least one deflected slit disc and is dissipated within the slit disc stack. a housing ; a vehicle seat disposed in the housing; and at least one radial slit disc energy attenuation assembly including an upper end coupled to the vehicle seat and a lower end coupled the housing; characterised by the at least one radial slit disc energy attenuation assembly including a slit disc stack having a plurality of deflectable discs configured to deflect in response to realizing a force applied by the vehicle seat; wherein the slit disc stack extends along a central axis, A, from a lower stack end to an upper stack end to define a stack height, wherein the plurality of deflectable discs comprise: a plurality of slit discs and a plurality of spacer discs , the plurality of slit discs, and the plurality of spacer discs vertically stacked in an alternating arrangement with respect to one another; and wherein the at least one radial slit disc energy attenuation assembly further includes a plunger extending from an upper end to a lower end, the lower end positioned proximate to the upper stack end and configured to penetrate the slit disc stack in response to receiving the collapsing force applied by the vehicle seat, wherein in response to penetrating the slit disc stack, energy is transferred to at least one deflected slit disc and is dissipated within the slit disc stack. a plurality of slit discs and a plurality of spacer discs , the plurality of slit discs, and the plurality of spacer discs vertically stacked in an alternating arrangement with respect to one another; and wherein the at least one radial slit disc energy attenuation assembly further includes a plunger extending from an upper end to a lower end, the lower end positioned proximate to the upper stack end and configured to penetrate the slit disc stack in response to receiving the collapsing force applied by the vehicle seat, wherein in response to penetrating the slit disc stack, energy is transferred to at least one deflected slit disc and is dissipated within the slit disc stack. <EOS>