A stiffening panel for a motor vehicle door, for example a side door. The stiffening panel is arranged between a structure of the door, which structure can be made of plastic, located on a side of a passenger compartment of the vehicle and configured to absorb majority of external impacts on the door, in particular front and side impacts on the side door, and at least one decorative outer panel which can be made of plastic and mounted on the structure. The stiffening panel can be made from a plastic material and stiffen the decorative outer panel to enable the outer panel to withstand external impacts on the door from the opposite side of the passenger compartment. The stiffening panel includes mounting elements for a window lift system. The stiffening panel is arranged between the decorative outer panel and a window supported by the window lift system mounted on the stiffening panel.

A side impact restraint protection system for a vehicle includes first and second side safety structures and first and second structural elements of a vehicle body structure. The first and second side safety structures are respectively connected to a first side door and a second side door. The first and second side doors are arranged to cover a common single door opening of the vehicle body structure. The first structural element is in a position in front of the door opening and the second structural element is in a position behind the door opening in a longitudinal direction. In the closed door position, the first and second side safety structures are releasably connected to each other via a connecting device, and the first and second side safety structures are respectively connected to the first and second structural elements via a first connection member and a second connection member.

A vehicle includes a vehicle body including a front pillar and a rear pillar spaced along a vehicle-longitudinal axis. The front pillar and the rear pillar define a door opening therebetween. A first track is supported by the front pillar and a second track is supported by the rear pillar. A bar extends from the first track to the second track. The bar is moveable relative to the first track and the second track from a lowered position to a raised position. The bar extends across the door opening in the raised position. The vehicle includes a cable that includes a first end and a second end. The first end is fixed to the bar and moveable with the bar from the lowered position to the raised position. The second end is fixed to the vehicle body.