These parts are made of a fiberglass shell with a rigid foam core. This gives the chassis tremendous strength while minimizing weight. In the molding process, metal 'hard points' are located in the fiberglass by the mold. External items, fenders, bumpers, suspension, etc., then bolt to these hard points on the chassis. Internal walls for the battery box and cockpit act as structural cross-members, adding to the integrity of the chassis.
All exterior surfaces are convex, making compression in an accident more difficult.
All corners have been rounded for maximum strength. There is only one door in the Sparrow, on the right side maximizing the strength of the left side. This will protect the driver in the common accident involving the left front corner of the car. Most of the weight of the vehicle is located within the triangle described by the three wheels, maximizing the stability of the Sparrow. The battery placement has been engineered to give an equal weight distribution on all three wheels.