A crash impact attenuator is adapted for deployment on a vehicle, and includes a cartridge portion having at least one energy absorbing module, as well as a backup system having a backup frame, which is adapted to attach the cartridge portion to the vehicle. The backup system includes an actuator configured to pivot the cartridge portion between a deployed orientation and a stored orientation about a pivot axis disposed on a lower half of the backup system. The backup system further includes a lockout frame member having a contact surface on one end thereof, the lockout frame member being actuatable between a deployed orientation wherein the contact surface engages a portion of the backup frame to support the backup frame against vehicular impact forces and a stowed orientation wherein the contact surface is not engaged with the backup frame.