A bicycle helmet that fits over a surface of a head of a user generally includes at least one segment of flexible cell structures that form a radial honeycomb matrix movable between a folded condition where each side of the at least one segment is disposed generally parallel and an expanded condition where the radial honeycomb matrix of the at least one segment is configured to be expanded at least partially over the head of the user and arranged radially relative to the surface of the head of the user.