This paper discusses mechanisms of spine fracture during racecar crash, and investigates possible modifications to the seat and driver restraint system to help reduce spine fracture risk. This study focused on an accident during the World Endurance Championship in which a driver sustained bony spine fractures at T11 and T12 as the racecar collided against the tire wall. Finite element (FE) simulations were analyzed to understand the spinal fracture mechanism, the driver kinematics and interactions between the driver and the seat/restraint system. This FE model incorporated the Total Human Model for Safety (THUMS) scaled to the driver size, a model of the detailed racecar cockpit and a model of the seat/restraint systems. A frontal impact deceleration pulse was applied to the cockpit model. In the simulation, the driver torso moved forward under the shoulder belt and the pelvis was restrained by the crotch belt and the front of the seat cushion. The simulation predicted spine fracture at T11 and T12 coinciding with those of the driver. It was found that a combination of bending moment and axial force at the spine caused the fractures. The bending moment and axial force were generated by the shoulder belt down force as the driver torso moved forward. The axial force at the spine was also induced by the forces from the crotch belt and the front of the seat cushion. Based on these mechanisms, the modifications were made to help reduce the spine fracture risk. The seat back angle was raised, the shoulder belt anchor was lifted, the crotch belt anchor was moved forward, the seat pad thickness was increased and the seat pad stiffness was reduced. These modifications allowed more forward motion of the pelvis and reduced the shoulder belt down force, and generated no spine fracture.