In one embodiment, a vehicle for transporting passengers can include a chassis, a support member, and a labyrinthine girder. The support member can be rigidly engaged to and project from the chassis. The labyrinthine girder can include a coupling platform that is coupled to the support member. The labyrinthine girder can form a partial enclosure that surrounds a portion of the frame rail. An offset distance can be disposed between the labyrinthine girder and the frame rail.