Located in the crevice between the two outer rear seats, this specimen is distinguished from its neighbors by a longer, thinner buckle stalk and a webbing path so convoluted it seems designed by committee, which in most cases it was. Where the window seats offer their belts freely, hanging ready at shoulder height, the middle belt is typically found wedged deep into the seat crack, sometimes fused to the upholstery by years of nobody reaching for it, requiring an act of genuine excavation to retrieve.
Its anchor point, when found, is often mounted to the ceiling rather than the pillar, giving the belt an odd diagonal drape across whichever unlucky occupant draws the short straw. That occupant, historically, is the smallest member of the family, or the newest friend, or whoever arrived last to the car and lost the unspoken negotiation over seating. The middle belt knows this. It has made its peace with being the seatbelt of last resort, the one buckled reluctantly, the one that leaves a faint red diagonal mark across the sternum as a kind of parting gift. In minivans it sometimes gets a proper headrest and a measure of dignity. In sedans it remains what it has always been: a strap for the person nobody planned for, doing its modest, essential job without complaint or company.