The majority of football concussions occur during tackles and other collisions and, thus, concussion associated with head impact is of primary concern for improving football helmet design. Our group is developing a helmet to minimize head-injury risk in head impacts in football. The Pro-Neck-Tor (PNT) football helmet consists of a commercially available football helmet outer shell and a custom carbon-fiber inner shell within the outer shell. A PNT mechanism is used to connect the two shells. Upon an impact to the top of the head, the PNT mechanism will deploy and the inner shell will rotate in either a flexion or extension manner. This deployment allows an escape path for the neck, provides acceleration ride-down, and significantly reduces head accelerations. Furthermore, in oblique impacts, the outer shell will deform into the void between the two shells, absorbing more energy than what padding alone can absorb. Testing conducted against a contemporary commercially available football helmet to show the effectiveness of the double-shell concept at mitigating head accelerations has shown reductions of 17 % in linear acceleration in impacts to the back of the head (velocity ∼ 3.0 m/s). In impacts to the top of the head (velocity ∼ 3.3 m/s) where the inner shell deployed, resultant linear head accelerations were reduced by approximately 38 %. Reductions in head rotational accelerations upward of 33 % were also recorded. The potential of a PNT helmet to prevent concussions in college football was estimated. The PNT helmet reduced the potential for concussion in every impact sustained and, in four instances, it decreased the potential from 85 %, 56 %, 83 %, and 77 % to 32 %, 15 %, 29 %, and 24 %, respectively.